How to edit a translation from the M3 real software?

Hi, I just got an M3 Real (did I mention I’ve bought a DS yet?) and everything’s fine, but I want to make a few modifications in the (lousy) Dutch translation. There’s this file called menu.hol which I can open in Notepad, but it’s hex.

Is there a special program for opening these specific files.

Thanks,
Davey.