7.1 on Onkyo 605s?

[mpstjohn]

I received my second set of Polk speakers a little while ago, and noticed after I hooked them up that now the sound comes out of the front (Polk 60s and Polk CS1) and rear speakers, but not the side speakers (Polk 50s). At any given time it can only output sound to five speakers, despite all seven being wired to the receiver. This same is true even when I'm watching blu-rays with 7.1 sound (Repo and 3:10 to Yuma).

On the menu there is a diagram that shows all seven speakers, two of which are not highlighted. I'm wondering if there is an option on the Onkyo 605s that would allow me to implement these two speakers.

Any help would be appreciated. Thanks.