Your Mac partition will not be directly bootable: MBR is not supported as a boot partition scheme (although we've had one user claim it worked, I've never been able to reproduce his result).

but when I backup all with SuperDupe I won't lose the MBR sheme - so i can give it a try and i don't have to be afraid of losing any of my data on the ntfs partition?

No, we won't touch the partition scheme.

I give it a try and it worked! There where any problems, no errors all went fine. First partition NTFS & second partition Mac OS Extended (Journaled)
with master boot record as partition table, after copying all data with SD, Mac OS X will boot from firewire. The ntfs partition still works fine.

At least I want to thanks for this extremely good and fast support!

I'm surprised that MBR worked. As I've said elsewhere, this must be something they added to more recent Mac firmware, or something... :)