Mojito:

Glad to hear the process worked for you!

I have not looked into requirements for coding a remote key with auxiliary heating/ventilation. My key fob does not have that capability, that is, it has no button for controlling auxiliary heating on the fob. It seems to me that there are two questions: (1) will Audi sell a key fob with the additional button and (2) will they code it?

If Audi will sell and provision the key fob, then that is probably the best way to proceed, that way all buttons on the key fob will work appropriately, albeit at some expense!

Instead, if your intention to source and provision an alternative remote control just for the auxiliary ventilation, then I defer to other readers of this thread - they can better advise you regarding what type of remote control to purchase, etc.