^^^^ Dang! You don't mess around.
I suppose you could always play it outloud and re-record it via speakerphone, but of course you do lose some quality.
Is it possible to play the message in the MOH port via burned CD on a CD player, play it into a phone while on hold, and then record it into a voice mail. I forget, is it possible to transfer a voice mail once on the system into a different mail box as a greeting?
DMS is much preferable. So many more options, but I realize you've got to work with what you've got.