Instructions
Load the game in your PS3 console and follow the prompts to resume where you left off.
Navigate through the game map to the point where you need to edit the onscreen value(s).
Press the "Action X" button on your PS3 controller when prompted to bring up an onscreen keypad.
Move the left thumb-stick around and press the "Action X" button to select the letters you want to enter.
Press the "Start" button when you're finished editing the values to save your entry and continue the game.