How to Disable Auto BT Connect with iPhone iPod to Ford Sync

One of the great combined features of my iPhone 3GS and my Fords Sync system is that if I have Bluetooth enabled, I can step into my car, the iPhone and Sync connect, and it automatically starts streaming music over Bluetooth from the iPhones iPod app via Sync to the vehicles audio system. Uses a LOT of power, and if I dont select a playlist, it will just start playing anything and everything in my library in no particular order. Generally speaking, it is very cool and works flawlessly.
The problem is, on those days when I do NOT want to play music from the iPhone, or drain the iPhones battery too quickly when Im out on the road, it doesnt matter. It still tries to connect, I have to manually go into the iPod functionality of the iPhone, and pause the playback, evidently theres no way to just the iPod app/functionality off temporarily. Then I forget, leave the car, come back, and have to do the same thing. Sometimes, I completely forget about this, but the iPhone doesnt. Even if Sync is turned off, the iPhone will continue playing, streaming to nothing, and unnecessarily running the battery down.
I need to keep Bluetooth on so that I can make handsfree calls when traveling. Sync doesn’t seem to have a feature or function that would allow me to connect when I want to, versus this standard automatic connection. I’ve tried switching Sync sources, etc. , doesn’t matter, when the iPhone senses a Bluetooth connection, it just wants to play music via the iPod app. And there doesn’t seem to be any setting for iPod or Bluetooth on the iPhone that will fix this situation as well.
Anyone have any ideas here? Very much appreciated in advance, thanks.
HP Desktop Windows 7 iPhone 3GS, iPod Touch 3G