One 100% gauarnteed way to accomplish this would be to create a code yourself. Although it's way easier said than done, but I do have possibly the BEST documentation to go from knowing nada to creating any kind of GS codes for any game. The amount of information here could make for a college...
I still have a running, soft-modded PS1, and have a GameShark as well. I remember when Action Replay replaced the GAmeShark well because I thought nothing could beat the awesome of the GameShark. Anyways, I might be able to help.