I have heard of this 'Mission Specialist' task. It is obviously not an MOC, nor is it even a qualification. While on Roto to Bosnia, I had a friend (Res Sergeant) who was a 'Mission Specialist' attached to 408 sqn. His job was exactly as mentioned: door gunner, observer, and he also (or so he told me) operated other 'equipment'.....basically whatever was attached to the helo (FLIR, C6, camera, etc), he would operate. My understanding is that it is a 031 tasking, must be Snr NCO/WO, and must have machine gunner qual......but this may have changed.