Busch Jäger 6737/01-84

I am trying to integrate a Busch Jäger 6737/01-84 control in openHab. Works so far, it is recognized as Busch Jäger RB01 with a total of 4 channels. The top two rockers are working perfectly, both as a switch control and as a level control. Unfortunately, the two bottom rockers don’t. If you press them, they only flash 4 times, which means according to the documentation that no scene is saved.

Any idea?