Thanks for the quick replies!
I do have a Strata DK280. I also found the manual! But it still fails to work. This is my procedure:
1) I hit intercom & dial "#604".
2) The LED on the phone prompts me for the ext#
3) I dial "232" (the ext#)
4) I dial "*16#" (16 second ringing)
5) The LED reads "2321" (the "1" is from the *16#" property - doesn't look right?)
6) The manual says I'll hear a "confirmation tone", which I never hear.(?)
7) I clear the forwarding with "#601" and try again - same result.

What is a pilot#? What is "dist hunt" ?
Should the "forward to" ext# be the voicemail box?
Is there an ext# for the voicemail?