No Sound on Front Audio ECS GeForce6100SM-M

I purchased a barbones system recently. I plugged in the wires from front panel to audio header on ECS GeForce6100SM-M but can't get audio/mike to work. The technician at the store claims that the ECS GeForce6100SM-M Motherboard front audio doesn't work unless rear audio is disabled by a jumper. "It's in the manual" he claimed though I could find no mention of it. I find this hard to believe as I've built systems using a variety of motherboards and have enjoyed both front and rear audio in parallel. Any truth to his claim?

FYI: I plugged the wires from motherboard which are labeled/connected to AUDIO1:

1 MIC
2 GND
3 MIC-IN
4 ------no wire
5 EAR RIGHT
6 EAR RIGHT
7 ------no wire
8 ------no wire
9 EAR LEFT
10 EAR LEFT

Cheers,
Danny