Just some brainstorming here, but is vgetty the right way to go for making outgoing calls? It would seem to me to be alot simpler, to use Device::Modem to take the modem offhook, dial the number, then wait for an answer. When an answer is detected( probably the hardest part of this ) , just use any audio app, like aplay, to play your message. You send the audio through a patch cord from the line out of your soundcard, to the line-in on the modem.

But I've never actually tried it.