Write on Digital I/O of ModBus

Hi all,

we have a UR10E connected to a windows pc running Node Red. Writing and reading to registers on the modbus works perfectly fine. However, we want to write to a Digital I/O now, that triggers the Auto-Start function. We managed to read it, but writing does not work.
How can we write properly on a digitl I/O?

Cheers :v: