I recently did my CCV and OFH, in the process of doing these 2 tandem jobs, I removed the alternator.
All the tricks are listed in the thread below.
You can disconnect the battery cable in the trunk if you wish. I didn't.
http://www.xoutpost.com/bmw-sav-foru...-overhaul.html
PS: Stick to Valeo or Bosch, brand-new if you can. Rebuilt alternators are hit and miss these days!!!