sound - 5 channel mode problem

Hello,
I have FC4 with a 5-channel sound card (Genius). I am also using ALSA.
The problem is that in Volume Control Properties there is no 5-channel mode. Only 4-channel mode, so I can't hear the central speaker. How can I solve this problem? What can I do to hear all 5 speakers?

Then, I want to have the possibility to control the volume of every speaker not only globally (It was possible in Windows). Any idea?


Thanks

class: AUDIO
bus: PCI
detached: 0
driver: snd-cmipci
desc: "C-Media Electronics Inc CM8738"
vendorId: 13f6
deviceId: 0111
subVendorId: 13f6
subDeviceId: 0111
pciType: 1
pcidom: 0
pcibus: 2
pcidev: d

open alsamixer and enable the channels you want. i don't think there is a way to control the volume of every speaker.