To edit the Aces of the Pacific roster you'll need a hex editor like the one found in PCTOOLS. Before editing I highly recomend that you save the ROSTER.DAT file to different directory or a floppy disk.

00: Number of Pilots on Roster
02-10: Name of Pilot
12-20: Backup Discription
23: Aircraft Insigna
00: Japan
01: US Navy & Marine Corps
02: Royal Air Force & Fleet Air Force
03: Chinese Air Force
04: Russian Air Force
05: Royal Netherlands Air Force
06: US Army Air Force
07: Royal Australian Air Force
24: Service Contry & Branch
00: US Navy
01: US Marine Corps
02: US Army Air Force
03: Japanese Navy
04: Japanese Air Force
05: Royal Air Force
06: Fleet Air Force
07: Royal Australian Air Force
08: Chinese Air Force
09: Russian Air Force
0A: Royal Netherlands Air Force
25: Rank (Although I don't know if it's necacary, I recommend that you use the apropet branch for you rank)