Yep, it's easy. You need the PS3 to Xbox tool here: (Don't worry that it's for 2012, works fine)
http://www.pesgaming.com/showthread.php?t=90183
Open the folder, put your PS3 folder into the Source PS3 Folders folder. Then you need a source scan file from your Xbox to put into the Source Xbox Files folder. You need to rename both the folder and the source file to include the number of the slot you want to use in game. (So that the Xbox's FACE___.bin file and the PS3's BLES01708EFACE___ [or whatever region code at the start] folder have the same number combination)
Once the two filenames are synced, you double click the "Pes 2012 PS3 Face Converter" file, wait for the dialogue box to come up and prompt you to 'rehash and resign' the file. You can press any key to close the window.
Then you go to the Output folder, and voila. You need to use Horizon to rehash/resign the FACE.bin file inside the 'Output' folder (guessing you know how to do this if you've been using save files etc.) but once you do that, you can copy it to your USB to move over.
I've made it sound way more complicated than it is - it takes seconds. Hope this helps!