Disconnect your battery and leave it half an hour, turn the wheel through 90 degrees and you'll find a nut in the back (about 6mm iirc) undo this, then turn 180 degrees the other way and do the same. The AIRBAG will come off then. Then you'll see the big nut in the middle.
Dont do it with the battery connected, theres a possibility that the airbag could go off in your face. And that fuckin hurts and deafens you trust me.