I tried to use the Microsoft AJAX Library in my custom help collection. The request went out but the response gave me an error, “Access is denied.“. I suspect this is caused by the same origin policy which prevents documents or scripts loaded from one origin from getting or setting properties of documents from a different origin. A web page in a help 2.0 collection frequently has problems in referencing files and does not exactly operate within a domain.
You can find additional information on this book at: http://www.packtpub.com/ajax-csharp-essentials/book