Hi everyone!
I found the solution for the problem myself. 
It is very simple.
In the RFXmgr Application which is running on Windows you choose the RFY ID in HEX. In openHAB you have to use the ID in DEC. This means, if you choose ID 0.12.01 in Windows you have to use the ID 0.18.01 in openHAB.
Hopefully this information is useful for someone else in the future.
Regards,
Bernd