Embedded resources in ASp.NET 2.0 are served up by a file listed as WebResources.axd. If your validators aren’t working, or treeview or sitemap images aren’t showing, see if the debugging steps at http://www.rosshawkins.net/rfh/articles/webresource.axd.html fix your problem.
However, if you’re running URLScan on your server, you may need to specifically allow the .axd extension in the .ini file. Once we did that, our sitemap was good as gold.