Well that's a bummer. But glad to hear that you have a workaround. Can't wait to see your final conclusion as I would also like to have the functionality of the ST2. So please share once you are finished!
I will certainly keep you all posted, I have already worked out a wiringloom with a minimum of work, the wires on pins 3 , 4 , 5 and 7 need to be cutted. This way you can use the handlebar switch combined with the new relay and ST2 module. For the indicators you can tap in the wires from the front indicators L+R , did a test yesterday with a mock-up install and it worked just fine. The only thing I do not have with test installation is the arrow indicator in the dash, need to find the wires from these. With the test I did there also where no fault codes so far.
But I had to process some bad news, my mother just passed away on just 2 months after my father. So I'm going to have to deal with that first, funeral, emptying the house and all the paperwork that it entails.
But if in the meantime someone might know which wires control the arrows in the dashboard, feel free to let me know, otherwise I will look into it, but it will not be right now.