Can answer this one myself, the trick is to use a RadAjaxTimer, which will "postback" to the server and then you can just do something like this:
if (radTabStrip.SelectedIndex < (radTabStrip.Tabs.Count - 1))
radTabStrip.SelectedIndex += 1;
radTabStrip.SelectedIndex = 0;
One thing though, it the Code example from Telerik it is said that the RadAjaxTimer needs to be in a Panel to work, but don't seem to notice any difference if it is in a panel or not, ie it works in both.