Hi @Arjan_Pas, did you get this sorted or do you still need help?
If you are using a “1-way normally open press to close switch”, that would be described as a Momentary switch in the Fibaro docs.
Also, FYI, I just updated the code today for the device handler you are using. It now supports full parameter synchronisation, multi-channel device associations, protection modes, fault reporting, and advanced logging options.