Hi
Usually, in the asterisk conf files we separate asterisk, our stuff and the customer stuff with a cascade of includes. However, although asterisk supports includes it doesn't always follow what's in 'em. Voicemail is a case in point. Turns out that if we had voicemail entries in an included file and a user changes her vmail password in the phone then asterisk wouldn't look in the includes so the change didn't get done. We had to move everything back into voicemail.conf and suppress the includes.
Best
S