Guitar Hero World Tour Wii

[Jason1]

My brother just got this for his birthday(his birthday was on the release date, ironically) Anyways for the life of us we cannot figure out why, but we cant get our microphone to work. I plug it into the USB port on Wii, and it like it never detects it. It just wont let you select vocal as an option, its always grayed out. And when you try to select it it tells you to connect a microphone. We've tried everything and we are really at a loss...any ideas?