Make sure there is a *17, short code, or any short code for voicemail collect
Put that code in the AA menu somewhere. (generally, I use *, set as a blind transfer to *17)
Thats it. If you make a short code to go to the AA, then internal people could transfer you to there, if they answer the call.
Again, there must be a password set, or you will get a recording saying you dont have access to remote.