A:Answer You need a special interface to have a camera hooked up to the factory screen. NavTV.com carries a lot of the interfaces. For your vehicle the interface is about $599. Another option would be to replace the mirror with one that has a display in it for the camera. Check what features are currently in your mirror because you may lose them (microphones for hands free phone calls, compass, garage door opener buttons, etc.)
Here's a link to the interface for your car: https://navtv.com/products/NTV-KIT725/bmw09n-dynamic-kit.html