Hi,I had the same issues but after a lot of messing about I managed to get my Plansonic BT H/S working with voice activation. I used the MS voice software and I had to install a bluetooth interface gateway whos name eludes me but I can find it out if neccessary.All the info is on this forum its just spread over lots of different threads,and I found that even then I had to faff about with various setting to get it to put the audio through the H/S and not the speaker,so you can do it, but it has a tendency to just not work when you want it to so I just press buttons on the phone instead.If you want the gateway sw name get back to me.
Rich