Log into VM admin via Cygwin or putty.
select the mailbox of the auto attendant.
ie. 5500 is the Auto Attendant number and mailbox number
Go to the Prof tab
Under Opts check the box after "Message on Demand"
Change the number of Node Level of MOD to 7
Exit and save changes.
The previous steps should only have to be done once per auto attendant.
From a phone press the voicemail button
Press the * key
enter Auto Attendant number
The first time you login you will have to setup the mailbox.
This is just like setting up your personal mailbox, but the only thing that is really important is the password which is currently 12345.
I usually just give the name of the Auto attendant for the mailbox name and greeting.
Once it has been setup press 9 for mailbox options
Press 6 for Auto Attendant administration
Press 1 to record greeting.
Follow directions to save and exit.