I tried the new Fiddler [1] inspector plugin [2] and it is working for the Atlas response, too! Atlas is returning an JSON string back to the client-side JavaScript that can be displayed as a tree view in Fiddler. Download the free Fiddler inspector plugin at http://ajaxpro.schwarz-interactive.de/download/AJAX.zip [2].
Interested to see what of the Ajax.NET Professional stuff is working in Atlas? Send me an email using the contact form [3] that we can have a meeting here at the PDC 05 in Los Angeles.