Wii U Surround Sound problem

I've been trying to hook my Wii U to my surround system so as to get the most out of Assassin's Creed IV, but right now I'm only getting sound and no visual. What am I doing wrong?

@PyreofKoL: Here's my assumption as you have not provided any details about how you have this setup.

1. You're using the Wii U HDMI

2. You have a surround sound receiver.

3. You have plugged your Wii U HDMI into your surround sound receiver.

4. You only get sound.

5. A second HDMI must go from your receiver to your television. This will give you video that you are missing.

Yeah, I did all of that right save for putting the HDMI's in the right ports on the receiver. I got it straightened out, but thanks for the help.