You can use any XML format to populate RadTabStrip with data. This example shows how you can load your XML file into XmlDocument and use the API of RadTabStrip and XmlDocument to create a hierarchical tabstrip.

If your XML is static and will not change, an even easier way is to use the built-in Visual Studio.NET designer - a convenient desktop user interface allows you to customize your tabstrip and the result is saved in inline in the aspx page.