Well I finally did a bit of searching and there are systems available that record victims. It was ofcourse presumptuous of me to think there might not be. A Japanese group has build a system. Their presentation to ETSI can be found here. It has a great name: I Am Alive. This system seems to be currently in use by the Thai governement and Red Crossat this moment.
The Australian governement has a system which is described here by the Red Cross which is using it. The system is called the National Registration and Inquiry System (NRIS).
I have seen the results of the the I Am Alive-system and it looks like an excellent system. It would be great if they could get some global support to further develop this system. At this moment it seems only Japan is working on this system and a quick search on Google didn't point too many English language pages on the system. I'll see if I can find some information on it.
I imagine every ministery of Interior, or government emergency response organisation should have a copy always ready and available on a webserver. So whenever there is a disaster this system is already running and can be used to register all the countries nationals potentially involved and can then later be used to compare these data with the records of the country affected. Maybe the United Nations Reliefweb website could be used as a basis.