You can't use Bluetooth with VA, or anything else for that matter, if your using high quality audio for both the speaker, and the mic. In order to use bluetooth with VA, you have to use Hands Free Audio for the speakers.
You can make VA use only the mic though, and use your computer speakers for audio if you wished, if not, the 8k hands free audio mode is the only option.
There are some specially made bluetooth headsets that allow, High quality audio from both the speakers and the mic at the same time, but you're going to pay for it, and I think they come with their own specially design bluetooth adapters to make it work.
I have a command in VA when I'm using my bluetooth headset, that it switches to just the mic, and uses my computer speakers. I just say, VoiceAttack Bluetooth, and it sets it up for me.