I purchased an A6 Avant in sept 2016, and are still waiting for this fix. The MMI is incomplete, as there are a number of settings you should be able to operate through the MMI that are simply "missing". Such as folding in mirrors when locking, one click uplocking, locking boot etc etc. I believe it has something to do with the fact they updated the Spec on the A6 and did not update the MMI to match.
You can take your car to a dealership who can program your key(s) as they did in my case to unlock all doors with one press of remote, and fold/unfold mirrors.
I am trying to chase this fix down with Audi UK