avdapmon is the debugging console of the VoiceMail box. Its a seperate exe in the avdap directory on the VM box.

You can dial a mailbox, and watch the debugging console to see which file it accesses. Or you can play an announcement and watch to see what file it accesses for the readout.

There's no easy way to map what the filename is to what the recording is other than converting and listening to each one otherwise.