I noticed that my previous post was perhaps a bit out of context since I never posted my Homelink installation in the first place.
Parts:
4B0971978B 6 pin homelink (pin MQS)
8E0971934 4 pin homelink (pin MQS isolated)
8E0907179 bracket for antenna
8E0909511 antenna
8N0959719 button module
The wiring is very easy. From the car you just need a GND, an ignition live (terminal 15) and one wire between the buttons and the antenna.
I placed the antenna on the battery bracket in the engine bay, since my battery lives in the boot, and the buttons in the little box below the light switch. Just run the wires as in the scheme. I added the ignition live to the buttons as a 'terminal 58d' so the lights will always be illuminated.
Now you have it all installed, you need to learn your garage remote to the homelink system. Check out the instructions, in German (super sorry).
Next up is the wiring to the button in center console. I took buttons 3G0927238K, that only have the rollo and nothing else. If you don't have the buttons yet, you need the connector too. T10ai = 6R0972930A. You can take the illumination signal and GND signals from the left side buttons.
The problem is, the Homelink switches connect to GND, and the wiring in the center console send out a 12V signal instead of GND. So, to fix this, replace pin 10, the common input, from a positive 12V to a GND.
Alternatively, if you do need the positive input/output, like when you have steering wheel heating already there, you can decide to keep the 12V output and use a relay to convert it to a GND.
The signal wire that comes out is now connected to the button module, specifically to the button switches.
Now if you press the rollo button, it sends a signal to the homelink button module, as if the actual button was pressed, and hey presto.
Alternatively you can buy the enhanced rear view mirror from VW USA with internal compass and homelink sender at part number 000 072 548A. I decided not to do this since it was about 300 euros AND it doesn't support the dimming exterior mirror.
All pics:
https://imgur.com/a/wViIYqT