Please, try to achieve the desired effect with the DecorationZoneID property, as its main function is to provide support for multiple skins on a single page. Unfortunately, this is the sole method for achieving this.
If you have problems with this, please, send us a small running project with the Vista skin and your custom skin as well, and we will try to put things to work for you.
the Telerik team
Check out Telerik Trainer
, the state of the art learning tool for Telerik products.