As far as I know, in SQL 2005, they removed IIS support for SQL XML.
The latest version that supports IIS is; SQLXML 3 SP 3. Actually I am using and loving IIS support of SQLXML on live systems. You can still use SQL XML 3.

Anyway, I needed the same features with authentication of SQLXML and I created a similiar application with .Net 2.0 which requires Enterprise Library January 2006 edition. Currently I am testing it with XP SP2 machine and it is working out pretty well.

My idea is to generate "Services" that contains "Atoms" (atomic actions, methods) on IIS, that way you can call sp with something like, http://www.domain.com/App/Services.Atom.ext?PRM1=1&PRM2=aa

You can download the code (binaries, Web Application and source) at,
http://workspaces.gotdotnet.com/MSServices
or
http://www.gotdotnet.com/Community/UserSamples/Details.aspx?SampleGuid=1B979D9E-351A-49D4-8F4C-8D583C6BB396

You need Enterprise Library January 2006 and Edition Visual Studio 2005 also IIS 5 or 6 and some Database connection. The configuration design is handled through Enterprise Libraries, Configuration Tool, the source uses many of the Application Blocks in Ent Lib.

You have executors (Database SP executor, MSMQ Executor, Assembly Executor, IronPython Executor or .NetCode Executor), the results of the executors are returned to the clients through generators (WebService, RSS, JSON, Excel or Text). 

If you want further discussion, you can contact me at mertsakarya@hotmail.com.

Regards,
Mert

function rss_GetNodeVal(node, XPath) {
 if(node==null) return "";
 var n = node.selectSingleNode(XPath);
 return (n==null) ? "" : n.text;
}

function rss_GetNodeValwBaseName(node, baseName, XPath) {
 if(node==null) return "";
 var n = node.childNodes;
 for(var i = 0; i < n.length; i++)
  if(n[i].nodeName==baseName+":"+XPath)
   return n[i].text; 
 return "";
}

function rss_GetAsDate(str) {
 if(str != "") try {
  return (new Date(str))
 } catch (e) {
  return new Date(0,0,0,0,0,0);
 } else
  return new Date(0,0,0,0,0,0);
}

function rss_GetAsW3CDTFDate(str) {
 //ISO 8601 - http://www.w3.org/TR/NOTE-datetime
 // YYYY-MM-DDThh:mm:ss.s+02:00
 if(str.length > 3) try {
  var year, month=1, day=1, hour=0, minute=0, sec=0, tzSign="", delta=0, tzSign=0, tzHour = 0, tzMinute = 0;
  year = parseInt(str.substr(0,4));
  month = (parseInt(str.substr(5,2))-1); if(isNaN(month)) month = 0;
  day = str.substr(8,2);if(day.substr(0,1)=="0") day = day.substr(1,1); day = parseInt(day);
  if(isNaN(day)) day = 1;
  var timePointer = str.indexOf("T");
  if(timePointer >= 0) {
   hour = parseInt(str.substr(timePointer+1,2)); if(isNaN(hour)) hour = 0;
   minute = parseInt(str.substr(timePointer+4,2)); if(isNaN(minute)) minute = 0;
   sec = parseInt(str.substr(timePointer+7,2)); if(isNaN(sec)) sec = 0;
  }
  if(str.length > 6) {
   var i;
   zSign = str.charAt(str.length-6);
   if((zSign=="+"||zSign=="-") && timePointer >= 0) {
    tzHour = parseInt(str.substr(str.length-5,2));
    tzMinute = parseInt(str.substr(str.length-2));
    if(isNaN(tzHour)) tzHour = 0;
    if(isNaN(tzMinute)) tzMinute = 0;
    tzMinute += (tzHour * 60);
    delta = ((zSign=="-") ? -1 : 1) * tzMinute * 60000;
    return new Date((Date.UTC(year, month, day, hour, minute, sec)) + delta);
   } //else if(str.charAt(str.length-1)=="Z")
  }
  return new Date(year, month, day, hour, minute, sec);
 } catch (e) {
  return new Date(0,0,0,0,0,0);
 } else
  return new Date(0,0,0,0,0,0);
}

function RSS(xmlNode) {
 this.XmlNode = xmlNode;
 this.Items = new Array();
 var verNode = xmlNode.documentElement.selectSingleNode("@version");
 var attr, i;
 this.ToHtml=rss_ChannelToHtml;
 this.DublinCore = this.Syndication = this.Content = this.RDF = this.wfw = this.slash = "";
 for(i=0; i < xmlNode.documentElement.attributes.length; i++) {
  attr = xmlNode.documentElement.attributes[i];
  if(attr.prefix == "xmlns") {
   switch(attr.value) {
    case "http://purl.org/dc/elements/1.1/": this.DublinCore = attr.baseName; break;
    case "http://purl.org/rss/1.0/modules/syndication/": this.Syndication = attr.baseName; break;
    case "http://purl.org/rss/1.0/modules/content/": this.Content = attr.baseName; break;
    case "http://www.w3.org/1999/02/22-rdf-syntax-ns#": this.RDF = attr.baseName; break;
    case "http://wellformedweb.org/CommentAPI/": this.wfw = attr.baseName; break;
    case "http://purl.org/rss/1.0/modules/slash/": this.slash = attr.baseName; break;    
   }
  }
  }
 this.Version = (xmlNode.documentElement.baseName=="RDF") ?  "1.0" :  ((verNode==null)?"0.9":verNode.text.substr(0,3));
 var tmpNode = this.XmlNode.documentElement.childNodes[0];
 this.Link = rss_GetNodeVal(tmpNode, "link");
 this.Title = rss_GetNodeVal(tmpNode, "title");
 this.Description = rss_GetNodeVal(tmpNode, "description");
 this.Language = rss_GetNodeVal(tmpNode, "language");
 this.Copyright = rss_GetNodeVal(tmpNode, "copyright");
 this.ManagingEditor = rss_GetNodeVal(tmpNode, "managingEditor");
 this.WebMaster = rss_GetNodeVal(tmpNode, "webMaster");
 this.PubDate = rss_GetAsDate(rss_GetNodeVal(tmpNode, "pubDate"));
 this.ModifiedDate = rss_GetAsDate((rss_GetNodeVal(tmpNode, "lastBuildDate")));
 this.Category = rss_GetNodeVal(tmpNode, "category");
 this.Category_Domain = rss_GetNodeVal(tmpNode, "category/@domain");
 this.Generator = rss_GetNodeVal(tmpNode, "generator");
 this.Docs = rss_GetNodeVal(tmpNode, "docs");
 this.Cloud = new RSSCloud(tmpNode.selectSingleNode("cloud"));
 this.Ttl = rss_GetNodeVal(tmpNode, "ttl");
 this.Image = new RSSImage(tmpNode.selectSingleNode("image"));
 this.Rating = rss_GetNodeVal(tmpNode, "rating");
 this.TextInput = new RSSTextInput(tmpNode.selectSingleNode("textInput"));
 this.SkipHours = rss_GetNodeVal(tmpNode, "skipHours");
 this.SkipDays = rss_GetNodeVal(tmpNode, "skipDays");
 if(this.DublinCore!="") {
  if(this.Language == "") this.Language = rss_GetNodeValwBaseName(tmpNode, this.DublinCore, "language");
  this.Creator = rss_GetNodeValwBaseName(tmpNode, this.DublinCore, "creator");
  this.Rights = rss_GetNodeValwBaseName(tmpNode, this.DublinCore, "rights");
 } else {
  this.Creator = this.Rights = "";
 }
 var nodes = tmpNode.selectNodes("item"), node;
 for(var i = 0; i < nodes.length; i ++) {
  node = nodes[i];
  this.Items.push(new RSSItem(node, this));
 }
 return this;
}

function RSSItem(xmlNode, owner) {
 this.XmlNode = xmlNode;
 this.Owner = owner;
 this.GetComments = rss_GetComments;
 this.ToString = rss_ItemToString;
 this.ToHtml = rss_ItemToHtml;

 this.Title = rss_GetNodeVal(xmlNode, "title");
 this.Link = rss_GetNodeVal(xmlNode, "link");
 this.Description = rss_GetNodeVal(xmlNode, "description");
 
 this.Enclosure = new RSSEnclosure(xmlNode.selectSingleNode("enclosure"));
 this.Image = new RSSImage(xmlNode.selectSingleNode("image"));
 this.Cloud = new RSSCloud(xmlNode.selectSingleNode("cloud"));
 this.TextInput = new RSSTextInput(xmlNode.selectSingleNode("textInput"));
 
 this.Body = rss_GetNodeVal(xmlNode, "body")
 this.Author = rss_GetNodeVal(xmlNode, "author");
 this.Category = rss_GetNodeVal(xmlNode, "category");
 this.Category_Domain = rss_GetNodeVal(xmlNode, "category/@domain");
 this.Comments = rss_GetNodeVal(xmlNode, "comments");
 this.Guid = rss_GetNodeVal(xmlNode, "guid");
 this.Guid_IsPermaLink = ( rss_GetNodeVal(xmlNode, "guid/@isPermaLink") != "false");
 this.PubDate = rss_GetAsDate(rss_GetNodeVal(xmlNode, "pubDate"));
 this.Source = rss_GetNodeVal(xmlNode, "source");
 this.Source_Url = rss_GetNodeVal(xmlNode, "source/@url");
 if(this.DublinCore!="") {
  //http://dublincore.org/documents/dcmi-terms/
  if(this.Author=="") this.Author= rss_GetNodeValwBaseName(xmlNode, owner.DublinCore, "creator");
  this.Date = rss_GetAsW3CDTFDate(rss_GetNodeValwBaseName(xmlNode, owner.DublinCore, "date"));
  this.Subject = rss_GetNodeValwBaseName(xmlNode, owner.DublinCore, "subject");
  this.Publisher = rss_GetNodeValwBaseName(xmlNode, owner.DublinCore, "publisher");
  this.Rights = rss_GetNodeValwBaseName(xmlNode, owner.DublinCore, "rights");
  this.Created = rss_GetAsW3CDTFDate(rss_GetNodeValwBaseName(xmlNode, owner.DublinCore, "created"));
  this.Valid = rss_GetAsW3CDTFDate(rss_GetNodeValwBaseName(xmlNode, owner.DublinCore, "valid"));
  this.Available = rss_GetAsW3CDTFDate(rss_GetNodeValwBaseName(xmlNode, owner.DublinCore, "available"));
  this.Issued = rss_GetAsW3CDTFDate(rss_GetNodeValwBaseName(xmlNode, owner.DublinCore, "issued"));
  this.Modified = rss_GetAsW3CDTFDate(rss_GetNodeValwBaseName(xmlNode, owner.DublinCore, "modified"));
 } else {
  this.Author = this.Subject = this.Publisher = this.Rights = "";
  this.Date = this.Created = this.Valid = this.Available = this.Issued = this.Modified = new Date(0,0,0,0,0,0);
 }
 if(this.wfw!="") {
  this.CommentAPI = rss_GetNodeValwBaseName(xmlNode, owner.wfw, "comment");
  this.CommentRSS = rss_GetNodeValwBaseName(xmlNode, owner.wfw, "commentRss");
 } else {
  this.CommentAPI = this.CommentRSS = "";
 }
 if(this.slash!="") {
  this.CommentCount = parseInt(rss_GetNodeValwBaseName(xmlNode, owner.slash, "comments"));
  if(isNaN(this.CommentCount)) this.CommentCount = 0;
 } else {
  this.CommentCount = 0;
 }
 if(this.Body=="" && this.Description != "")
  this.Body = this.Description;
 return this;
}

function RSSCloud(xmlNode) {
 this.XmlNode = xmlNode;
 this.Domain = rss_GetNodeVal(xmlNode, "@domain");
 this.Port = rss_GetNodeVal(xmlNode, "@port");
 this.Path = rss_GetNodeVal(xmlNode, "@path");
 this.RegisterProcedure = rss_GetNodeVal(xmlNode, "@registerProcedure");
 this.Protocol = rss_GetNodeVal(xmlNode, "@protocol");
 return this;
}

function RSSTextInput(xmlNode) {
 this.XmlNode = xmlNode;
 this.Title = rss_GetNodeVal(xmlNode, "title");
 this.Description = rss_GetNodeVal(xmlNode, "description");
 this.Name = rss_GetNodeVal(xmlNode, "name");
 this.Link = rss_GetNodeVal(xmlNode, "link");
 return this;
}

function RSSImage(xmlNode) {
 this.XmlNode = xmlNode;
 this.Title = rss_GetNodeVal(xmlNode, "title");
 this.Description = rss_GetNodeVal(xmlNode, "description");
 this.Name = rss_GetNodeVal(xmlNode, "name");
 this.Link = rss_GetNodeVal(xmlNode, "link");
 this.Url= rss_GetNodeVal(xmlNode, "url");
 this.Width = rss_GetNodeVal(xmlNode, "width");
 this.Height= rss_GetNodeVal(xmlNode, "height");
 this.Width = (this.Width=="")?88:parseInt(this.Width);
 if(this.Width>144) this.Width = 144;
 this.Height = (this.Height=="")?31:parseInt(this.Height);
 if(this.Height>400) this.Height = 400;
 return this;
}

function RSSEnclosure(xmlNode) {
 this.XmlNode = xmlNode;
 this.Url = rss_GetNodeVal(xmlNode, "url");
 this.Length = rss_GetNodeVal(xmlNode, "length");
 this.Type = rss_GetNodeVal(xmlNode, "type");
 return this;
}

function rss_GetComments() {
 if(this.CommentRSS != '')
  return loadRSS(this.CommentRSS);
}

function rss_ItemToString() {
var txt = 'Channel Link = {Channel_Link}"\n\r'+
   'Channel Title = {Channel_Title}\n\r'+
   'Channel Image Title = {Channel_Img_Title}\n\r'+
   'Channel Image Url = {Channel_Img_Url}\n\r'+
   'Channel Image Link = {Channel_Img_Link}\n\r'+
   'Channel Image Width = {Channel_Img_Width}\n\r'+
   'Channel Image Height = {Channel_Img_Height}\n\r'+
   'Item_Link = {Item_Link}\n\r'+
   'Item_Title = {Item_Title}\n\r'+
   'Item_Author = {Item_Author}\n\r'+
   'Item_Comments = {Item_Comments}\n\r'+
   'Item_CommentCount = {Item_CommentCount}\n\r'+
   'Item_Body = {Item_Body}\n\r';
 return _rss_Item_replace(txt, this);
}

function rss_ItemToHtml() {
 var html = '<table width="100%" bgcolor="#cccccc" cellpadding="0" cellspacing="0" border="0">'+
     '<tr><td>'+
      ((this.Owner.Image.Url=='')?'':'<a href="{Channel_Img_Link}"><img align="left" border="0" src="{Channel_Img_Url}" alt="{Channel_Img_Title}" width="{Channel_Img_Width}" height="{Channel_Img_Height}"></a>')+
      '&nbsp;<a href="{Channel_Link}" class="black"><b>Feed: </b>{Channel_Title}</a><br/>'+
      '&nbsp;<a href="{Item_Link}" class="black"><b>Title: </b>{Item_Title}</a>'+
     '</td><td align="right">'+
      ((this.Author=='')?'':'<b>Author: </b>{Item_Author}<br/>')+
      ((this.Comments=='')?'':'<a href="{Item_Comments}" class="black">{Item_CommentCount} Comments</a>')+
     '</td></tr>'+
     '<tr bgcolor="#666666" height="1"><td colspan="2"></td></tr>'+
    '</table>'+
    '<table width="100%" cellpadding="2" cellspacing="2" border="0"><tr><td>'+
     '{Item_Body}'+
    '</td></tr>'+
    '</table>';
 return _rss_Item_replace(html, this);
}

function _rss_Item_replace(data, item) {
 return data.replace(/{Channel_Link}/gi, item.Owner.Link
   ).replace( /{Channel_Title}/gi, item.Owner.Title
   ).replace( /{Channel_Img_Link}/gi, item.Owner.Image.Link
   ).replace( /{Channel_Img_Url}/gi, item.Owner.Image.Url
   ).replace( /{Channel_Img_Title}/gi, item.Owner.Image.Title
   ).replace( /{Channel_Img_Width}/gi, item.Owner.Image.Width
   ).replace( /{Channel_Img_Height}/gi, item.Owner.Image.Height
   ).replace( /{Item_Link}/gi, item.Link
   ).replace( /{Item_Title}/gi, item.Title
   ).replace( /{Item_Author}/gi, item.Author
   ).replace( /{Item_Comments}/gi, item.Comments
   ).replace( /{Item_CommentCount}/gi, item.CommentCount
   ).replace( /{Item_Body}/gi, item.Body
   );
}

function rss_ChannelToHtml() {
 var aHtml = new Array();
 aHtml.push('<table width="100%" class="d" cellpadding="0" cellspacing="0" border="0">');
 aHtml.push('<tr><th>Title</th><th>Date</th><th>Author</th><th>Subject</th><th>Category</th></tr>');
 for(var i = 0; i < this.Items.length; i++)
  aHtml.push(rss_DrawChannelItemAsHtml(this.Items[i],i));
 aHtml.push('</table>');
 return aHtml.join('');
}

function rss_DrawChannelItemAsHtml(item, line) {
 var arHtml = new Array();
 arHtml.push("<tr>"); 
 arHtml.push('<td><a href="#" onClick="drawLine('+line+')" class="black">'+item.Title+'</a></td>');
 arHtml.push('<td>'+item.Date.toLocaleString()+'</td>');
 arHtml.push('<td>'+item.Author+'</td>');
 arHtml.push('<td>'+item.Subject+'</td>');
 arHtml.push('<td>'+item.Category+'</td>');
 arHtml.push("</tr>"); 
 return arHtml.join('');
}