If you boil it down, it's actually pretty simple.
take the tension of the spring, one bolt out and flick the star wheel to tighten it.
you will however spend ages trying to line the wheel bolt hole up, and flicking the wheel around to figure out which way to turn it!
from memory, drivers side, the adjuster is at 10.30 on the clock. I think it works out with a wheelbolt at exactly 6oclock.
It's easier with the wheel off, and you can get close enough to see if it's tightened all the way in, or expanding out and you can see some threads starting to show.
I'm struggling to find a decent close up pic, but the star wheel in a nut that just jacks out a threaded section like a bolt. If you can't see the threaded section, it's tightened fully in.
for the passenger side, the expander is at 1.30ish on the clock scale.
that's the fella.http://www.pelicanparts.com/bmw/techart ... stment.htm
that's a general guide, 1 series spec is spring off, tighten the star wheel so the wheel doesn't move by hand, and back off 8 clicks.
(if you don't back off the full 8 clicks, the spring under the handbrake lever might keep it on for you!)