nForce audio no center channel

Hey guys, I've got an Abit NF7-S V2 mobo with the Soundstorm audio. I've never been able to get the center channel using my Z-5300 speakers. These speakers have a green, black, & yellow audio jacks. The mobo has these as well. However, in order for the surrounds to work, I have to swap the black and yellow connections. If I don't, the channels I do get are all mixed up. This really irritates me.

I know the center channel speaker itself does work, because depending on how I adjust the options in the nForce control panel I can get sound from it, but then the other speakers don't work correctly.

This is very irritating and any help would be appreciated.