Good morning, Steffen,
I was misled by the title of your message.
Your vehicle is not an A4 8K produced after 2011, but rather an
A6 4F with a production date of 05/2011.
Therefore, the codings for the Au48 platform will not work on your
AU56 platform.
The required coding is different, and VCDS will display the coding options within the program. The necessary login codes (if required) will also be displayed in the program when you hover your mouse over the respective field.
Here are the notes from Ross-Tech:
http://wiki.ross-tech.com/wiki/index.php/Trailer_Hitch_Retrofitting_(4F)
Best regards and good luck.
Michael.