You can move the messages (at least the Custom Service Menu's) using the system back-up under utilities.
I was able to do this and migrate Custom Service Menu recordings to the NS series. Not sure how it would do with Mailbox Prompts, but it would be worth a shot.
When I backed up and restored the CSM greetings, here is what I found.
It backs up all of the greetings in one file. But it's not quite smart enough to recognize any skips i.e. CSM's 1, 2, 4, 6, 7, 8. It will drop them back in order 1, 2, 3, 4, 5, 6. So you need to record a short script of some sorts in the ones that are skipped (3 & 5) so you have consecutive greetings (1, 2, 3, 4, 5, 6, 7, 8). Then when restored they are put back consecutive order.
If that works at least you don't have to do 100% of it from scratch.
Edward
