While this thread is a little older, I wanted to post an update on this. Kenwood has posted an updated Bluetooth module on their site (version 1.60)that resolves the issue with the Blackberry Curve. I have the 8310 and had to use a work-around previously to get it to automatically connect. Since installing the bluetooth module update from Kenwood, I have not have a bit of problem. The phone automatically syncs and I also have use of the address book, recent calls, etc.
I can't post a link yet, but go to Kenwood USA site, then to support, and then to the Technical & Firmware/Software Downloads under Car Entertainment. Look under Support for "About the Bluetooth Module firmware updater".