1) Get a friend with a decent net connection and meet them in a room.
2) Take the items you want to dupe out of your bank, and make sure they appear in your personal inventory.
3) Quit and Save the game.
4) Go back online and re-enter the room your friend is in.
5) Drop the items you want to dupe. Make sure your friend picks your items up in case of a network failure (in that case your shit dissappears!).
6) Don't talk or dilly dally while your in the room, if you do, the dupe usually won't be successful.
7) Pull the DC power plug from the wall. DO NOT PRESS THE POWER BUTTON IN!! THIS WILL BSOD YOU!! LEAVE IT PRESSED IN THE ON POSITION!!
8) Wait about ten seconds, then plug the power cord back into the socket.
9) Go back to the room your friend is waiting in. You should both now have copies of the items you wanted duplicated.
MASS DUPLICATION!! The duping process runs on a basic on a basic math formula. Say we just completed the duping process on one of the best swords in the game, the Lavis Cannon, and now we have two of them. If we save the game with 2 cannons in your personal inventory, then dupe again, your friend will have 2 and you will have 2. This takes a little time to do, but it is REALLY worth it. Keep in mind though that you can only have 30 items in personal inventory, and 60 items in your bank, so plan out your trading strategy well. I personally keep 4 characters, one store each of the main class of weapon, and one to store mags and armor. You can very easily collect every item in the game by duping, so have fun with it. WE MUST PUNISH SEGA FOR THEIR WRONGDOING!!