If it works in the back and not from the motherboard header, check to see how many pins are going to the motherboard header.
Many motherboard headers had 9 pins, but if the devices plugged in there use all 9 pins usb 2.0 will mess up with over a 128 MB flash drive.
This is a common problem for many front usb connections. The solution is to cut the extra 9th wire. Successfully used on a MSI 845 board with a Coolermaster case.
I know this has worked on Antec cases, but I don't know if the P-160 is one of them. Please verify here if it is.
Jim