WD Media Player won't play NERO 5 channel surround audio

This thread is about the Western digital WD TV HD Media Player. Click here to see full specs

I bought the WD Media Player so I could recode my DVD's to my hard drive and play them through the WD player. All is fine except NERO recodes Dolby 5-channel surround in ACC codex. Western Digital Media player won't process the sound through its optical port. All I get is a loud hum. They claim they are processing Dolby surround through the HDMI port but that doesn't help as I am using a Bose Lifestyle 18 surround sound system and that need a digital / optical input. They claim they support a Dolby codex but I don't know what exactly that is. Does anybody know how I can recode my movies in high def with Dolby surround sound and make it play through the WD Media Player?