Chimera 5.1+PC 5.1

So I bought the Chimera 5.1 wireless headset. But I have yet to be able to get it to actually run in 5.1. My mother board is a MSI 790X-G45 with a built in 6 port audio jack with no sound card. This is what the back of the chimera dock looks like. http://drh2.img.digitalriver.com/DR...oduct/gallery/razer-chimaera-5.1-gallery6.jpg

The guide says I will get 5.1 if I connect a 3.5m to RCA cord (which i had to buy separately) But this method only gets me R/L audio. Any ideas how to actually get this to work in 5.1?

 

So I contacted razer customer support and was told that I would be unable to get 5.1 sound without a digital optical port (which they fail to mention on the website.)