in the setup menu of your receiver, under basic settings, speaker settings, the menu where you choose to set the speakers to small, larger, and set the crossover, it gives you the option to choose prioirity for the 6th and 7th channels, either surround back, or presence speakers, you need to make sure you select surround back. The only other thing you need to check is that you select the proper audio stream from the menu on the blu ray, some discs, especially Warner Bros. movies default to the non lossless audio track.