Asterisk as an Auto Attendant for CUCM

I had a question come up the other day. I’ve learned that Cisco Unified Communications Manager does NOT come with an Auto Attendant. In order to get a Cisco AA, you must purchase a Unity product to get it.

My question is, can I use Asterisk as voicemail and AA module for CUCM? I’ve successfully used Asterisk for a voicemail module, but I’ve never attempted to use it as a AA module.

Anyone have any ideas?