In the installation folder of RadControls for Silverlight you should have the complete styles for the RadDocking. For example on my computer they are located here:
C:\Program Files (x86)\Telerik\RadControls for Silverlight Q2 2011\Themes\OfficeBlack\Themes\Office\Black\Docking.xaml
You could copy the styles from there.
the Telerik team
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