Help adding new Zigbee Roller Shutter Controller

Ah, didn‘t think of that. Be careful, if you are not familiar with household installations - the operation voltage is dangerous.
It should also be possible, to do this with HA on-board methods using code.
I found a thread with a workaround here.
In Zigbee2MQTT there is an invert cover Boolean for that purpose.
Probably not too difficult to implement in ZHA as well - but have no time to look into this.
I assume, that the Merten Bridge also had such a setting, so the electrician is free to choose the Installation orientation to fit the Situation best