E53 retrofit

[Mr_hog]

Hi, I've llooked through the site but can;t seem to get the answer I need! I am about to retrofit nav into my X5. Today I did a test run in the back of the car to see if it all worked and most of it did (I basically plugged everything together and added my loom to the main loom of the car). There was power to the CD changer, the nav computer and the board monitor. However, although the screen did come on when I turned the ignition on - I could get nothing more than a blank screen - none of the menu screens that I was expecting. I know you have to get the car recoded for the nav to work in sync with the rest of the cars electrics but does anyone know if the car has to be recoded to get the menu screens?? Any help would be much appreciated, thanks