Hi Daniel @damator
To keep all similar to FSR14x4 control it could make sense to use the Setpoint from GVFS in Funktionsgruppe 3.
My plan was to implement some new messages for the PTM EEP to mimic a simple rocker switch (finished this already). In this case you could control the operation mode (normal, night, reduced and off) and receive the current state of an FHK14. If you want to set the setpoint too, we have to find the right EEP first. I could not find any hints about the EEP but would guess to use the A5-38-08 subcommand 0x04 basic setpoint. However I am not sure how the FHK will react to the different setpoints set by openhab through this EEP and the setpoint coming from your room panel. The documentation is not clear at this point if openhab would overwrite the roompanel in this case 
So testing would be really neccessary. Which openhab version do you use?
I will fix the problem with the unknown ESP2Packet in the next release. I thought that the gateway would never receive a Transmit_Radio_Telegram. I expected that it would be changed to a Receive_Radio_Telegram.
Best regards
Daniel