Audi A6 avant 2004 isofix?

[GunnarThor]

Hi, hope english is ok at the moment. I am looking for the Isofix montings in the back, that I can put in myself. Cannot find it in any store I check.
If someone knows anything or has a part car with it, I really want to buy. Should also fit from A4 and possibly passat.

Best regards.