The installer manual is pretty sketchy on the on-board AA. The Sys Coordinator (Admin manual) has better information on this.
Feature codes are F*81x. I always have to look up which do what. Turning Sys Answer on and off, and CCR on and off are both done in config programming.
I only have one customer that uses this, and over the years, I've really regretted not pushing them into a true VM system. Some things are worth the extra few bucks.