Save files from other users can be loaded by the Final Fantasy XIII game but it says that if the file is loaded that the game cannot be saved and the loaded save file cannot be overwritten.

Is there a file in the save file that can be edited to eliminate this restriction?

List of files in the save file sub-folder:

APP.DAT
ICON0.PNG
PARAM.PFD
PARAM.SFO

Because maybe if the user information of the save file is edited to match the user information in the console then this restriction can be bypassed.

Or is it possible to modify the Final Fantasy XIII software so that the code that disables the save function can be erased?