SpaceMouse buttons not showing up in RH settings

My SpaceMouse Pro Wireless buttons are not showing up correctly in the RH settings - only buttons 1 to 8 are shown, however the SpaceMouse has 15 assignable buttons. Luckily there is a thread about the button assignment procedure here.

However I would still be great if one could just assign the commands simply in the Rhino settings, as this would be much less cumbersome and could be changed much quicker.

Greetings,
Rudi