Receiver won't detect dts- hd master audio, 5.1 pcm, etc from blu rays?

I recently bought an Insignia 5.1 system and I have it connected to my PS3 via hdmi cables and I'm having trouble getting the receiver to recognize different sound formats. I have alternated making my ps3 output bitsream and pcm but I am still at a loss. Most of my blu rays are coded with dts hd master audio and my receiver has the ability to decode all the formats that are used but for some reason I cannot get it to work properly. It has no problem recognizing dolby digital 5.1 from blu rays and DVDs but whenever I try to get it to play from a source other then DD it just acts like the input is plain old stereo sound and I'm not getting the sound the way it was intended. Any help would be greatly appreciated as I want to hear the sound the way it was intended