Yeah, but bottom line is you can't embed the mailbox number and/or the pound, and the password and pound onto a speed dial button.
On some Partner systems, I have looped an intercom station to a CO port, and assigned that CO line to a phone. Then you go off hook on that button and press the speed dial button to get one touch access to voice mail.
On a Legend, you should be able to do the looping, put the CO line in a pool, and program the pool, access number, pauses, and password on a button?