Found this page for rear fog retrofit from another person on the web. Seems he has done the retrofit on his 01 touring and it works like OEM. I'm gonna give it a try once I have the time. But it looks like I'll have to add the front fog kit first...
http://members.cox.net/kokayasu/BMW/howto/Rear_fog_retrofit.html
http://members.cox.net/kokayasu/BMW/howto/Rear_fog_retrofit.html