Alright guys, I installed it successful (what a wondeful OS) ...
The first time, I booted without any flag and the configurator started.

Then I had to restart (loading, loading ...).

The second time, I booted without any flag and the apple screen appeared a second and the pc rebooted (the third time, too).
I started with -x mode (alright) and with -f mode (alright, too), but two things doesn't want to run:
- my internet connection doesn't work
- my second monitor (20" plugged in about a DVI) doesn't want to work (my 19" plugged in about VGA works) (at startup, the white screen and the apple logo appears on both screens)
I think that's it. All I tested was nearly fully working. ;-)