At the moment we are working on the new RadEditor for ASP.NET AJAX for MOSS (v.5.0) documentation and it will be available online until Tuesday. Note that the new documentation will be part of the RadControls for ASP.NET AJAX one (http://www.telerik.com/help/aspnet-ajax/introduction.html
) - the section is called Integrating RadControls in MOSS.
Please excuse us for the temporary inconvenience.
the Telerik team