Only after changing 3 apparently good pad wear sensors to new ones did the warning reset sucessfully using the odo button/BC button.
I also tried using my AutoEnginuity ODB tool and it refused to reset. I tried the reset procedure using the odo button and the BC button on the turn signal stalk, but it refused to reset. I double checked all 3 pad sensors, and they were intact. It said all pads had to be replaced (based on mileage, not actual wear of the pad sensors which were tied off due to frequent pad swaps for the track). My 2008 M3 Coupe brake pad warning light came on as a result of the service indicator counting down to zero. I thought I would post my experience with this issue since I see a lot of questions about it.