Can't save in Pokemon Colosseum while on the Wii?

Pokemon Colosseum is a game originally meant for the Gamecube, but can be played on the Wii. I'm having trouble saving my game on the Wii. I have a 2GB memory card I'm using (you know, the thin one you can use in cameras?), but my game's not being saved. Funny though, because when I play Supersmash Bros. Brawl, I can save my pics and what not onto it. Should I be using a Gamecube memory card instead?