there is a possibilty......
simply put i noticed, that when you select the 'install' option on the PS3, the whole game gets copied to the HDD. the cd is only needed to authenticate the game.
now if you plug the HDD into a pc, apparently the GameOS partition isnt seen properly, if there is a way to get into there then bobs ur uncle and pes can be edited.
i think however there may be a software or driver in the future that'll allow you yo access that partition....
hope that theory helps. because technically there is a clear possibilty, just one hurdle in the way...