The front panel lines connect to the FP_AUDIO connector. This page gives detailed descriptions and tells you what the pin numbers are.
mic-in - (pin 1) mic2 gnd - (pin 2) agnd mic-bias - (pin 3) micpwr spkout R - (pin 5) line out_R return R - (pin 6) BLINE_OUT_R spkout L - (pin 9) line out_L return L - (pin 10) BLINE_OUT_L
I'm not sure exactly how you've connected them. Have you connected two USB ports or four? USB_56 has two USB ports and USB_78 has another couple of ports. The two pairs are identical. Most of the time you connect a monolithic connector to the motherboard rather than separate wires and it's keyed so you can't screw up.I currently have the USB 1 wires in the 56 slots and the USB 2 wires in the 78 slots