Sorry for my English reply, I can't write German very well.

It is most likely possible that the touchscreen of the Galaxy supports multitouch. The source code of the kernel of the Behold II (a different Samsung android phone) contains a kernal that is built for the Behold and the Galaxy. It also contains functionality to flash the firmware of the touchscreen, including a binary dump of touchscreen firmware for the Samsung galaxy.

This means the touchscreen can be updated and it might be possible to make multitouch work. It also means it is very likely that samsung is planning to update the touchscreen software, perhaps to make multitouch possible.