I used a hex editor to change the games id so I could load both games into usb loader.
If you delete the happy face from the id the game will not load from disc or usb loader.
With the happyface there the usb loader will not recognize the cover for it.
Found this on the web: "I finally realized after hours of gaming, the games are literally connected together through memory. Example, say you play DISC 2, which is basically story solo mode only. You get a character to about level 50 or so. You decide you want to play your friend in versus mode and pop DISC 1 in. When you choose that character you leveled up, he will have everything you had from DISC 2. That's why the IDs are the same."
Hope this helps.