What can I do with the RadAjaxPanel to force a partial postback and refresh/update all the controls inside it? I used to use an UpdatePanel and call .Update()
To achieve the desired result, you can call the ajaxRequest() method of the ajax panel. A similar setup is demonstrated in the following article:
http://www.telerik.com/help/aspnet-ajax/ajxinteractionbetweenpanels.html