Hi Stefan Handke,
Actually, the Silverlight controls cannot be automatically installed in the VS ToolBox. This is a limitation right now. We working in this direction. For the rest of the controls - I suggest that you try to rest the toolbox and let us know how this goes.
As for the "not merged help" problem - we could not reproduce this problem at our side. Could you please send the help log file to us. It is located at RadControlsInstallationFolder\Documentation\H2Reg_Log.txt. You can zip the file and attach it to a new support thread.
Thanks for your time and cooperation.
All the best,
the Telerik team