Are you looking for page head updates during ajax requests? If yes, try to use the EnablePageHeadUpdate property of the telerik ajax manager or panel. In case you want to register the skins of the controls after async request, set their EnableAjaxSkinRendering property as in this example: http://demos.telerik.com/aspnet-ajax/ajax/examples/common/showingwebcontrols/defaultcs.aspx
I see what you mean now. I doubt what you want is attainable because as far as I know the ajax manager/panel cannot update elements outside of the body tag. I stand corrected though, especially if you can manage to that with MS UpdatePanels.