Abu,
do you know where you want to install the camera? if you look at picture of my X5, you will notice the camera right above the first zero in plate number
004D665|99rus.
is it where you want to install it? Let's find a good power source for the camera and lets route the video cable from camera to where your video module is located...
one thing at a time...
Also, forget about the reverse lights altogether, you will have problems if you use them...