Right, but I have several roles and I want to drive it off the sitemap file like this:

<siteMapNode url="~/UserProfile.aspx" title="Profile" description="" roles="*" />

<siteMapNode url="~/Admin/Default.aspx" title="Admin" description="" roles="Admin" />

<siteMapNode url="~/Seller/Storefronts/Default.aspx" title="Storefronts" description="" roles="Seller"/>

Not sure how much conditional logic you can cram into a page without code-behind. I'm also not sure what I need to import to get "User.Identity.IsInRole" to resolve.