You can do eboot modding. Use TrueAncestor to decrypt your game's eboot, add the codes, encrypt it back to normal, copy to PS3, and you're good to go. I don't remember how to make packages, and packages don't always work, so that's your gamble if you go the package route. Your EBOOT.BIN is at HDD0:GAMESyourgamenamePS3_GAMEUSRDIREBOOT.BIN.
You could also try actually using Artemis too. https://github.com/haxxxen/ArtemisPS3
There's also NetCheat, PS3EMPM, CMP Auto Tools, and probably other various tools I don't know about.