Thanx for the answers! I am a little late, because I was not online. I installed Windows XP (sorry for that ;-) for testing purpose, but later about that point.
For the xorgconfig (as root) you must know the frequencies (that I don't have, or better: I got some parameters by testing with Windows XP) or use the standard vesa modes up to 1280x1024, but that already works, not with nvidia though ...
Also the README.txt from NVIDIA is of no help in this case, because there are no informations about the frequencies. I already tried to find out something with read-edid over ddc, but that doesn't work with the Samsung LCD under Linux. When I found out that I tried to disable ddc, but still no result.
I then decided to install Window XP for testing and wrote down the different frequencies for the differnet resolutions, but that also doesn't work when I modified the xorg.conf. All modes had 60 Hz for vertical sync.
Now I am back on Linux, but Nvidia still doesn't work and vesa only with 1280x1024 instead of 1680x1050 and mplayer with vesa ... no joy !
The thing is, that the xorg-log has no errors ! I just don't see anything, so there must be a problem with the frequencies, I guess.
And by the way the driver for the intel hda also doesn't work right now, there is a weird whistleing on one channel ...
So there is still a lot of work to do for the Samsung M70 (did I mention that the SD card reader also doesn't work right now ?)
But never give up ... there will be a solution. So I still wait for suggestions ... and call Samsung again ...