To get the roster onto your PS3. Download the roster onto a USB.
On your USB make a folder called ‘PS3’ then in that folder another called ‘SAVEDATA’ then put the roster file ‘BLUS30078-ROS...etc.’ into that folder.
Eject you’re USB properly and plug it into your PS3. When your are on your PS3 home screen (not in the game yet) go to ‘Save Data Utility’ you’ll see the USB listed, click on it and select the roster file then click ‘Copy’. Fire up the game and the roster will load automatically and if not then load them from inside the game.
If problems arise, its your usb, format it then try again or get a different usb.