nhmaf is right on the socket. If you need to buy a modified one, his is the one. I have heard of Craftsman working, however. I've also heard that every frame is unique.
On the driveshaft/output flange bolts, they are, indeed 12 point, 10mm bolts.
The 10x12mm box end wrench that comes with the BMW tool kit is shorter than your average wrench, but with it you have all the leverage you need to tighten the bolts. Loosening the previous install might be another story.
With that little wrench, you just put it on a bolt, stand on the rear brake with one foot, and give it all you can with the 10x12.
I've never had one come loose, and my method has the Duane Ausherman seal of approval.
And it is a really cool wrench.