The Professional DNN
provider of RadEditor that comes with the DNN 5+ installation, is implemented by DotNetNuke
developers and it is not supported by Telerik.
My suggestion is to post the question about how to configure RadEditor in the DNN forums
. For example in this one: Taming (customizing) The new Telerik RadEditor
the Telerik team
If you want to get updates on new releases, tips and tricks and sneak peeks at our product labs directly from the developers working on the RadControls for ASP.NET AJAX, subscribe to their blog feed