I am trying to connect my frontal usb ports to my mobo, but i cant seem to find where the cable goes on the mobo. the case is a corsair air 540 and the mobo is an asus p9x79, the cables coming from the 2 ss usb ports are connected and end in what looks like a 20pin plug but closer together and smaller than the other pins with one of the corner pins filled in. help?!