No 7.1 only 5.1?

Hey,
First off if this is the wrong section then I apologize.

I am using this card http://www.newegg.com/Product/Product.aspx?Item=N82E168... . I have a mini hdmi to regular hdmi cable that I am using to connect from the video card to my receiver. I am also using windows 7 64 bit.

I can go into the control panel, manage audio devices, configure, then speaker setup and set the system as 7.1. Although when I test the speakers only the side surrounds make noise and not the rear surrounds. When I click on the rear surrounds the corresponding side surround makes noise instead. When I click on the sub in the same window it does make noise. Although no applications I use, whether its music or games, trigger the sub. So I only seem to get 5.0 sound out of music or games.

Any ideas or help would be greatly appreciated.

Thanks