thanks to ronaldojr and firefan98 for the list of "face ids of players no longer in fifa 13"
now when you create a new player you have to possibility to choose from a list of players that has their own graphic files in game but that are not used (like Del Piero, Owen...), the editor will assign that id to the newly created player so that it uses that graphic files.
so if you want to create Del Piero just choose him. All player data (and I mean all, name included) will be random cause the player doesn't exist in the database (you have to manual set them as any othe new player) but graphics like playersheet, face and hair will be the original ones.
here's an example of what i mean