Hey DNA:

Did you get this to work yet?

The voice mail is most likely getting the follow-on ID of the outgoing message extension, by default 5XX. Try setting up a mailbox with the same number as the outgoing message, put a simple greeting in it to verify that's the case.

Let us know if I am right. There are a few work arounds to get the message put in the same mailbox as the overflow box.

Edward

Edward