Perhaps I'm a little naïve with regards to Nortel gear, but I would expect it to continue down the call path designated in the system.

DID's may be directed to handsets, but they're terminated at the PBX (at least in my mind). The voicemail, and call handling configuration is not related to, or controlled by the handset ... so it seems counter intuitive that unplugging a handset from the wall would result in an origin carrier "feature not supported" message when the PBX has other options (not even a PBX generated message).

My whole objective at the moment is getting some headless DIDs as we have ~100 DIDs, and only ~50 handsets. There are a lot of people that work remotely 100% of the time, and just use their desk phones in the office for voicemail. We have lots of empty desks for new people to sit at, but all of the phones are in use ... my initial plan was to just pull the wires in the closet and re-land them on unused ports; but as soon as I pull the wires, the old numbers go dead and even the voicemail stops working.

My initial assumption was that there may be a setting in the BCM to ignore handset status that I just couldn't find ... but maybe there is an entirely different approach that I need to take for this problem?