FabStyle-Msg-Tool
A tool for FabStyle msgsec###.dat message files
Place the DS version's msgsec###.dat files in the DS folder, and/or the 3DS version's msgsec###.dat files in the 3DS folder. (Both folders go in the same location as the .exe file.)
Then you can extract the messages from those files, as well as making new .dat files from the extracted message files.