Just did this tonight. Both buttons. Since I have an '08, I had to perform the Lego mod. However, in my case, it was the dowel rod and Duplo mod
This creation, combined with one or two felt pads was sufficient to bridge the gap between the buttons at front and the circuit board at the back.
Thanks, OP, and all who contributed to the thread!
Updates:
Rear fogs work just fine. However, I'm getting no dash lights indicating such on my very early-model 2008 launch E90. Also, unless I gummed up the top, instant-on headlight button (certainly a possibility), I'm not getting this functionality--lights on auto, press button: nothin'. I'll update later if things change and I'm able to get this button to work as intended.
OK, so maybe I was smoking something the other night. Turns out, the rear fog dash light is working for me. I think I may have not seen it the previous night. Then, when I was checking it during the next day, the headlights weren't on. Therefore, it makes sense that the rear fogs wouldn't come on then