If its anything like the m20, its kind of a pain... but I rigged it
. I got about a 2 foot pipe, and wedged it inbetween on the the little pully bolts, and either the frame on the drivers side, of the abs box, anything thats sturdy. I then got a big ass wrench and twisted toward the drivers side (its lefthand threaded). Although a bmw tool will make it easier im sure, i was cheap, and still am, so i did it my way.
Again im not a pro with the m10, but on the m20 you do need to remove the tranny plate that covers the back of the oil pan. You probably have torx bolts there, you can get a little set at autozone for pretty cheap.