Got my iPhone today and I'm excited. I want to use it in my car and so the following. 1 - Mount it. 2 - Charge it. 3 - Play music on it via an aux-in. 4 - If an incoming call comes, I can take it. From what I gather, option 4 is the problem child. I have a battery powered bluetooth handsfree kit. Could I use this in conjunction with the charging, music playing iphone?