The basics:
You need to figure out the Voice Mail ports, based on which slot the Partner Messaging is installed in, and what other cards are slotted before it.
Once you know those, program the VM ports in to Hunt Group 7 with #505-7-XX-1, where XX is the extension number. Do this for both ports.
Set the transfer return extension for each of the voice mail ports to point to Ext. 10, for transfers to extensions without mailboxes, with #306-XX-10.
Assign the lines to be answered by the Auto Attendant with #206-7-LL-1, where LL is the 2-digit line number.
Set the number of rings before answering, with #506-M-LL-X, where M is the Mode (1=Day/2-Night), LL is the 2-digit line number, and X is the number of rings from 0 to 6.
Log into the System Administrator's mailbox in the Partner Messaging, select 9 for programming, 3 for Auto Attendant, 1 for Day or 2 for Night, 6 to Modify, enter your selector code, 6 to Change, select your option from the menu and specify an extension if appropiate, *# when finished changing selector codes, press 1 to record the prompt at the tone, and 1 to end the recording, finally *# to approve the changes and recording.
Keep in mind if you also want your callers to be able to dial extension numbers, and your extensions start at 10 and go up to whatever, keep those matching selector codes set to "Direct Extension Dial", and use something like "press 3 for this and 4 for that...."