Thank you very much. Your suggestion of using rollershutter-control is spot on - it works fine
I hesitated to use it, because in the binding description, it says only to be used when OH owns the state. In my case a physical KNX actuator owns the state. But it works fine to have the OH *-conntrol side by side with this. And I simply need the info to do an enhanced state presentation in my UI as I wrote in another message also in this post.