I'd like to weigh in on this, living in Germany --
From what the Lechhausen BMW Autohaus has told me, to get an American e60 to work correctly with a rear Fog, you would need a whole new rear drivers side trail light housing AND the correct switch AND an hour of programming. This normally only happens when someone permanently transfers an American BMW to Germany, where it will spend its remaining days there. If it is done temporarily they can do some voodoo computer magic so the rear drivers side brake light gets a full +12V when the fog light button for the front is pushed. Essentially you lose the ability to control the fog lights independently like you can with the DDM market BMWs.