I am curious to know if I can add template data via the Client-Side api much like the way you can do this server-side. Such as the way you do it in example: http://demos.telerik.com/aspnet-ajax/menu/examples/functionality/templates/defaultcs.aspx
I have been able to achieve this server-side by adding this to a root item:
Dim ChildItem As Telerik.Web.UI.RadMenuItem = New Telerik.Web.UI.RadMenuItem("MyControl")
(The user control has the html)
I've gotten close to the functionality. I've added this code to a root item:
var item = new Telerik.Web.UI.RadMenuItem();
item.set_text('<div style="width: 100px; height: 150px">My template data</div>');
This actually works but it appears to have the menu item functionality overlaid.