Creative Live! 5.1 & Home theater system.

[Vampire]

I have a Creative Live! XGamer 5.1 sound card and I recently bought a 5.1 home theater system, but the problem is that my card doesn't support a digital optical output, but my home theater system also has a coaxial input and I have a cable that comes with it. The cable is a RCA cable and the sound card output is minijack, so I have a RCA to minijack cable so I can connect my reciever to the sound card, I read in the Creative support site that you need a mono minijack cable ( 2 pole ) so I got one and soldered it to the cable and connected it from my reciever to the sound card, the problem is that only my front left and front right speakers work, not the rest. I've made sure everything's set up right ( drivers, reciever settings ), and have also tried it on my brother's pc, it worked fine on that one using an optical cable and immediatly recognized a 5.1 signal. Any idea on what could be wrong?

[R600]

I'm not too sure about the XGamer sound card, but there should be a digital coaxial output on the card itself. Plug the RCA cable into this port and into the coaxial input of your speakers and in windows, make sure that in the sound settings, there is Digital Output only.

[Vampire]

It's a RCA to Minijack cable because the sound card has a minijack output, but it's connected properly and digital output is on, if it were off there would be no sound.