First of all, I really appreciate the tips for getting this fixed. I also ran the battery down (all the way, no less) and suffered the ill-fated stuck starter. I charged the battery, and tried again, but none of the tricks worked. I thought I was going to be resigned to hunting down that darn relay to bang on it or pry it open, when the local BMW mechanic gave me this routine. He said it works EVERY time. He was right, as it worked first try for me.
1. With negative cable disconnected charge battery to full. If it's an old or bad battery that won't take a full charge, replace it before going to the next step.
2. After battery is fully charged, with key on, hold starter button down, and then reconnect the neg. battery.
3. As soon as you connect the battery, the bike should start. After the bike starts, release the starter button.
4. With the bike running, tap the starter button once or twice QUICKLY.
5. Turn the bike off, and she's all fixed.
I hope this helps!