Anyone have documentation on Zune Marketplace Search Links?

I'm trying to figure a way to provide a search link to the Zune Marketplace from another program, and can't find any documentation on this.

To compare, one can link to Amazon using the following:
http://www.amazon.com/exec/obidos/external-search?mode=music&keyword=U2%20Joshua%20Tree

The "keyword" term is very simple to use and flexible, allowing you to pass terms that make sense and are available from other sources.  If you are pulling a playlist in XML or from LAST.FM or wherever, you probably have enough information to populate a query that is useful.

For Zune, I can find the following:
http://social.zune.net/external/launchclient.aspx

But, to launch to the same U2 Joshua Tree, you need to enter:
http://social.zune.net/external/launchclient.aspx?mtype=Album&mid=7b4ab500-0100-11db-89ca-0019b92a3933

This 'mid' code is not readily available nor intuitive.  Does anyone know of a way to call the Marketplace search routine, either using launchclient.aspx or another method?  I know that the zune:// prefix can be used to launch the client software, but again cannot find any documentation on keywords (e.g., "zune://search?query=U2+Joshua+Tree" or something to that effect).

What I am trying to build is an XM Radio listener that can work with the Zune Marketplace.  Ultimately, I'd like to have the listener monitor a station (e.g., 1st Wave) for a time, then be able to mark all the songs for easy retrieval from Zune.  If you have a Zune Pass, it'd be great to pass an XML file of dozens of songs you wish to download.  Step one, though, is to figure out how to do a simple search.

Any help is appreciated!!