Hey Mike,
Thanks for your replay.
It has to be: keyboard model: auto, keyboard layout: (empty). Does that help?
This configuration is like Keyboard model: pc105/de, Keyboard layout: de. (If I press '4' on the numpad(num is lock), I get sometimes '4' and sometimes the cursor goes one position to the left)
However, there is something new that I found out about my problem: If Num is locked bevor establishing the remote session it works (until I unlock and lock it again). The problem occur only if I lock Num during the session.
Michael