First things to do is to create two save squads in the game:
1-Enter FIFA12 and go to MY PROFILE-»SAVE/LOAD/DELETE-»SAVE-»SQUADS and make a new squads save you'll have now two squads files
2-Do the same again but this time overwrite the Squads 1 save, this will make the game load the first Squad when you enter the game.
3.copy my save to a usb stick
4-now in multiman file manager on one side of the aplication browse to the current user that you use to play FIFA12
example mine is: dev_HDD0/home/00000001/savedata/BLES013810101/
5-in the other side go to the folder where you have my save
6-copy the files PARAM.PFD and SYS-DATA from my save to dev_HDD0/home/00000001/savedata/BLES013810101/
Exit multiman and start FIFA12
7-go to MY PROFILE-»SAVE/LOAD/DELETE-»LOAD-»SQUADS and load Squads 2
now we are going to check if it worked, go to KICK MATCH and choose Juventus and see if the default is like the one on this image DO NOT START THE MATCH its only to see if the the squads updated:
Now go back to MY PROFILE-»SAVE/LOAD/DELETE-»SAVE-»SQUADS and overwrite the Squads 1, this way you'll not get a corrupted save anymore.
Enjoy the game.