Redskin
Howie is right about the forwarding status, but you might what to use an XVM key so the call does not ring the phone at all, but goes right to the mailbox. It would help to know what system and voice mail you have the Compact starts as a 4X8 and there is a DS16 also know as a DCS616. The voice mail will be different for both of these systems as well. When the auto attendant answers the calls go to the right mailboxes because it's programmed to do so and not ring the phone first.
I have mine set that way, in the day mode the extension rings and in the night mode you can only leave a message.