Help with beta modding!

Hey! so im trying to get SinglePlayerCommands installed for beta 1.7.3, and I have tried everything i can think of to get it to work. I've tried installing the jar for the mod directly by running it, ive tried using old mod loaders, ive tried manual installation by dragging the class files for the mod into the minecraft.jar file (tried that with the old mod loaders too), ive even used multiple different launchers (betacraft, multiMC, normal launcher), and i CANNOT get it to work. it either breaks and gives me an infinite black screen, or the game loads but the mod just isnt there. anyone know what im doing wrong? Thanks!

(Heres where I got the mod's jar from if it helps: Single Player Commands – MCArchive)