I believe that the following demo exemplifies the appearance that you are trying to achive. Give it a try and let me know if this helps.
Considering the Radcontrols for winforms, Telerik reporting and Siteinfinity CMS I would recommend that you open separate support tickets so that you can get the most competent answer by people from the different teams who work with the respective environment/technology.
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