One of the keys I've received with my 2006 sportback doesn't allow me to lock/unlock the car via the buttons. I can use that key to unlock the car and drive away without any problems. Having disassembled the remote (see 2006 Audi A3 sportback remote components | Flickr - Photo Sharing!) I can see that the RFID chip is separate so that is fine. I do have VCDS and have played around with various suggestions on the Ross Tech website and also contacted them early last year regarding this issue but wasn't able to make any progress.
Can I buy another key off the bay and swap in the PCB? Is that my best option to getting a fully functional key?