Trying to get surround sound working with Digital and Analog from Onboard and Card?

So I've been goin' nuts with this for about a week.

So I recently purchased a 1000W Sony Home Theater System (BDVN-5200W) which is my main outgoing audio system. What I had before this was a Razer Leviathan.

My main audio for the Sony is connected via Optical / SPDIF and the main reason I'm keeping this one my motherboard is so I can keep the SupremeFX sound from my Motherboard

My motherboard is the ASUS Maximus VII Hero.

Now what I'm trying to do is set my old Leviathan, and use it as strict surround sound, behind me.

I was told you cannot use 2 audio channels on the same board at once so you needed to buy a sound card... so I did. I bought the ASUS Xonar DGX PCI-E 5.1 card.

I hook up the Leviathan through the black surround port on there and now here's where I'm stuck.

I updated the drivers, and all that, but now I have 2 Stereo Mixers in my Recording tab in my sounds options. One from the Realtek (my default Optical) and the Xonar.

I've been swapping around with the Listen to this Device, bull for over 3 hours and I'm NOT getting any surround sound at all when gaming.

Could someone PLEASE tell me what I'm doing wrong and please guide me through if possible?

Main Audio is Optical
Surround is Analog

My Default Audio device is set to the Realtek Digital on my Motherboard.

If you need any other info, please please ask... I really don't wanna think I wasted money here...