No sound on my Z68 pro3 gen3 thru it's optical out

[Sini]

I am using the specified motherboard and I have the realtek drivers installed (latest). But I can't get the sound to go thru my optical cable directly to my receiver--which supports DTS Dolby digital and Thx standards. I have the latest bios 1.2 on the motherboard, I have 12gb of RAM Win7 Ultimate 64 i7 2600k and it's installed on my SSD Muskin chronos series drive 60 gb.When I go under sound properties it shows that the optical is activated and the green bar is activated but no sound still-and I do make it a default device for sound. So if someone can help me regarding this issue I would appreciate it a lot,
thanks in advance!