I use the 9 pin port to my aux port in my car, all hidden away inside the dash. I realize this is a long way around, but it charges, and plays audio in the car, it's all hidden away, and I had all of it lying around already...
I use the Apple composite AV Cable only hooking up the Left and Right audio cables. I use the USB plug into a hidden USB adapter to power and charge the phone.
http://store.apple.com/us/product/MC748ZM/A/apple-composite-av-cable?fnode=3a
From the Left and Right audio out I run into a Y splitter. 2 RCA Female into 1 3.5mm (1/8") male adapter.
http://www.bhphotovideo.com/bnh/controller/home?O=&sku=216446&is=REG&A=details&Q=
One 3.5mm to 3.5mm Female to female coupler.
http://www.radioshack.com/product/index.jsp?productId=2102697
A standard 3.5mm to 3.5mm cable.
http://www.radioshack.com/product/index.jsp?productId=4344796
I run the Apple 30 pin to Lightning (.02) Adapter into the 30 pin Apple composite AV cable.
http://store.apple.com/us/product/MD824ZM/A/lightning-to-30-pin-adapter-02-m?fnode=3a