In the mean time, I needed to torque down the flywheel and attach the clutch and pressure plate. Realizing I needed to lock the flywheel in place, I started looking around for some way to do it. I ended up using a leftover piece of channel iron, a long bolt and a C clamp to hold the bolt down.
I realize this means I'm dangerously close to achieving the status of "redneck", but BMW wanted crazy money for the "official" tool. Anyway, here's a good picture of the whole assembly.
Next, I have to get some replacement hardware to bolt the tranny up to the motor assembly.