SPDIF OUT not working on Asus P5AD2

[Max]

Can someone help me with this problem, which Asus support hasn't been able
to resolve?
My PC is composed by:
Asus P5AD2 Premium
Intel 540 CPU
Intel Pentium 4 540J
2 X Corsair CM2X512-5400C4
MAXIMO Radeon X700PRO 256MB PCI-E
Hitachi Deskstar 7K250 250GB 8MB SATA
The problem is that the SPDIF OUT isn't working because it isn't available
in windows (in the mixer infact it not present); the others output works
correctly and recognise when a connector is plugged in, but there is no way
to make the SPDIF OUT recognise a plugged connector.
I use these drivers: - Intel Inf V6.2.1.1001
- Cmedia CMI9880 Audio V5.12.01.0008.51.61
and I have Windows XP Professional SP2.
What could be the problem?

Thanks everyboby

 

[Ginchy]

does it need to be enabled in bios?

 

[Max]

does it need to be enabled in bios?

Unfortunately in the Bios in can only Enable or disable all the integrated
sound card.

Thanks for interesting on my problem!