Well, I've integrated such a 4CH China relay package into my Y3 Diagnostic System:flybobbie said:I have a simple 4ch remote switching relays.
There must be some signal that perhaps is replicated in smart top to tell the system in effect ignition is on to close roof.

https://z4-forum.com/forum/viewtopic.php?t=134505
2 channels are for opening or closing the roof by putting the according input ports to ground (simulating the internal buttons).
2 channels are for opening or closing the front locking system independant of the roof for maintenance and diagnostics.
The prerequisite for using these 4 functions with my system is that the key is inserted into the FOB slot in the car. But the ignition is NOT required to control the functions mentioned.
So far I don't know how the roof modules activate the car's environment, but I'm pretty sure they send a message on the redirected CAN bus.