So, there is no way to just leave it unlocked when you drive? I don't use exchange, so I'm not in the exact situation you are, but I do remember that when I was running a custom 6.5 ROM on my diamond it would never pair with my phone if it was locked. Asleep is fine, so I just don't lock my phone when I drive ... it's got a special place in the glove box where it likes to sit.
This is prolly no help, but I think it is just how the new Bluetooth stack works.