I wish the composite cables would....

[tbone7467]

I just ponied up the 50 bucks to get me a set of composite cables for my Iphone. I wanted to beable to use my iphone in my car so my passangers could watch movies from it on the mobile screens installed. One of the things i thought it would be able to do was transmit sound over my car stereo. What i mean is have my phone hooked into the stereo and when a call came through play the call throught the stereo and use the speaker phone part or bluetooth headset to reply to the caller. That and have the caller ID or SMS message alerts pop up on the screen so that i knew if i needed to pull over to reply to a Business need from my company. These options donts seem like they work either that or im doing something wrong.