You can add a 'translation' box to make them do things... but that's not easy or cheap to do as a one-off.
For example, I have a Parrot aftermarket bluetooth module which has a third-party steering wheel translator box to read the phone buttons... Now I can pick up, hang up, redial etc. from the steering wheel button.
-Interestingly, the in-dash display still says 'NO FUNCTION' because the car itself doesn't "know" that something else is 'hearing' the same serial instruction and "making sense" of it.
Not that button... but if you PRESS the
thumbwheel NEXT to it, the radio 'SCAN' is activated... -I think you must have been confused and pressed the other button.
Link to the kit which I have, incl. video showing installation and operation (not me or my car in the video)
http://www.quickconnectproducts.com/Find/VWsteer2.htm
Keith