I can't bind to the Mode property of the BingRestMapProvider. The BingRestMapProvider is not part of the visual tree. This worked in Silverlight and I thought it worked in previous version of WPF as well.
Aleksandar, BingRestMapProvider can be defined in XAML via the Provider or Providers properties of the RadMap but does not automatically take the DataContext of the RadMap. Yes, it is not part of the visual tree and it has no visual parts at all. You need to manually set its DataContext or bind it to the DataCotnext of the RadMap. In Silverlight this probably works automatically because of the differences between WPF and Silverlight XAML parsers.