Carputer & Bluetooth with PDANet, Handmark Handshare or Pebbles

I am using my Treo 650 as a carputer connected via a PC to an 8" monitor in my car. All of these programs work great via USB cable, but unfortunately only one of these can run at a time. These 3 programs all have Bluetooth connectivity, but I can not get any of them to work.
For anyone using any of these programs via Bluetooth, is there any secret to setting them up properly? Through searching, some are using PDANet Bluetooth - are there any specific setup instructions? Anyone have one of the other two programs working via Bluetooth? Any help is appreciated. Thanks!!!!