the one i mention above is not for mod your own save. it is for how to transfer the save to your xbox...
as you see, each game save of xbox got it own id. like my id is different then yours. you must know ur own id 1st...
here is the tutorial how to game save: http://www.maxconsole.net/showthread...Your-HDD-PICS&
for using usb, it is more easy, just google search for modio then use it to open your usb and edit the id..., the step is like the link i show you...