Thank you for all your great suggestions. The reason, I would like to do a [transfer, extension, release] in a single button, is to transfer an incoming call to the user voice mail box in a one shot.
currently what i have programmed is an autodial.
Example:
incoming call for ext 2020
assistant [ext2021] picks up his line
incoming caller wants to leave a vm for ext2020.
assistant presses [transfer] [autodial=transfer to vm], she dials ext 2020, and then release.
Secretarial flashes, rings, and assistant can answer and transfer, but still has to do the three steps process.
Our vendor told us 'it CAN'T be done'..but there is got to be a way. Avaya had it, and Mitel is such a good system, it has to be it

I will keep playing with the 'Line Type'
thanks again, and if anyone has other suggestion, please let me know.