Hi gladmo2, As with some of the others, I haven't had much to do with the 308 and have only played with a couple of 824's. I am guessing they use the same software etc.
I maybe wrong but you may be able the DISA-AA to transfer to an extn and use that extn to divert to BV (voice mail).
I have a copy of a basic setup if you need a look (just may need to figure out how to get it to you)

Ps, in the Extension/Feature Settings under the type column set your call foward status (FWD Busy N/A) and choose the destination (BV is at the BOTTOM of the extn list)
Cheers Olley
If all this is no help, let me know, and I will hunt out the manuals!!!

Last edited by Olley; 06/09/13 05:21 AM.