#208 Call Coverage will get the call to the mailbox, as long as you set #206 to 2, and be sure that the line appears and rings on the extension.

Mike's instructions on setting #206 to 3 and programming Line Ownership within the VM is valid as well.

The difference is: Does the line appear on any other extensions? Does the covering/owning extension use DND? Do you want to be able to answer the line from any other extension before the VM answers IF the covering/owning extension in on DND?

Coverage: The DND makes the call go to VM immediately
Ownership: The call still rings on other sets even if the the owner is on DND.