How to get the Final Fantasy XIII game to accept save files from another user without restrictions

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?

Additionally, I just recently downloaded a decryption software to edit the APP.DAT file to change the user or system ID but the decrypted file is in hexadecimal format. Does anyone here have a hexadecimal to human readable text converter software so I can modify the user or system ID to match the ones in my unit?

Additionally the converter may not be needed, I just need someone to tell me where the line of code containing the user and system ID can be found. By creating a new save game at the earliest save point, I can simply copy the data on the line of code from the APP.DAT file that contains the ID's of the new game save and transfer it to the same line of code on the APP.DAT file of the game save that I want to use and the game will accept it without restrictions.