No sound from front panel of GIGABYTE GA-MA69G-S3H

Question

Case: A-Top Gladiator AT878BK-CMotherboard: GIGABYTE GA-MA69G-S3HAs per the manual, in the Realtec HD Audio supports both rear and front panel audio ports simultaneously. However, I hear sound from rear panel only. I have connected the Case front panel connector to the MB front panel pins. In fact the key connector matches with the MB pin layout.There is no documentation for the Case.I could not find any settings in the BIOS or the Realtec control panel.Can you please advise what seems to be problem.Thanks in advance.-Aloke