The car has a "battery manager" which controls the charging of the battery, it will start to shut down non essential parts of the car, should the battery start to fail. This is the device that needs to know the type of battery, so it knows what it is dealing with.
As long as you get the same type (capacity) of battery and change it, there is no recoding to be done.
Just go to euro car parts and get their recommended battery, replace it and you should be good to go.
Why do you need to change it on an 06 car?
I have a 05 3.0tdi quattro, and battery is as strong as ever, I had a problem with it going dead if left for a few days, turned out to be the radio not shutting down when car turned off, had to update the MMI software (which has an update to the radio in it) and never failed since. I remember the VARTA battery for my car was £150 odd at that time.
If you have the same problem then changing battery will not fix it - if you need more info, let me know.