HomeLink mirror for Three with ADP and Three Touring

I apologize for creating a thread about HomeLink mirror next to another one about the rear view mirror. But we really need to separate these two models from 2 and 3 without ADP . In another thread in Accessories and modifications, based on which and on my own experience, the after market mirror cannot be installed on Three + ADP or Three Touring. However some people reported it was possible on 2.

When I bought my 3T some 10 days ago, I paid additional $400 to a dealer to install an after market auto dimmed HomeLink. They told me there would be no problem. But when the guy arrived, he looked at the bulge on the windshield where camera and sensors are located, scratched his head and said he never did it for this model. He was able to open it and install his mirror but it could not be turned around, just did not fit. He put everything back, apologized and now I am getting a refund from the dealer, who was surprised as much as the guy and I! At least he did not break the cover as 'CHC' reported in abovementioned thread.

I asked the dealer if it was possible to install a mirror from Four but the answer was negative. I am curious why? They told me different wiring but all that is needed is a ground and 12 V if I understand correctly. I know there are a lot of very technical folks on this forum, Can anybody confirm it is not possible in principle? Somehow I suspect it may be possible. I was at the dealership today servicing another car and had a look at Four's HomeLink. It has exactly the longer 'neck' needed to be able to use it mounted on the top of sensors. Maybe there is not something they can automate and produce in mass, but a small modification could work? Or is this path also closed? If so, I guess, all we (people with 3T and 3 ADP) can do is wait till someone produces a mirror that will fit.