Finally I had some time and replaced the drivers windows switch assembly. Here are the results of first hand testing
(have in mind this was done on a LHD car):
Audi A2 drivers windows switch assembly: 8Z0 959 851
Audi A4 B6/B7 factory windows switch assembly: 8E0 959 851 B (fully compatible)
Audi A2 mirror switch: 8E0 959 565 A
Audi A4 B6/B7 mirror switch: 8E0 959 565 A (fully compatible)
Audi A2 passenger window switch: 8Z0 959 855
Audi A4 B6/B7 passenger window switch (NOT COMPATIBLE WITH A2 SWITCH): 8ED 959 855
I will try to find a genuine Audi A4 B6/B7 switch assebly with exactly the same symbols, if not successfull this switch assembly works perfect. I have checked a new non Audi switch assembly and they all have the same symbols as the currenty installed one.
Here is also a video of the replacement with the comparison of the switches: