No Dolby True HD signal?

Hello all,

I'm a HT novice but just connected my new Denon 4308ci to my PS3 for some lossless audio goodness. I put in Nightmare Before Christmas which is encoded with a Dolby True HD 7.1 soundtrack. The receiver shows that it is playing a 7.1 soundtrack but reads multi channel 7.1 not dolby true hd. I'm assuming that it isn't playing the best possible soundtrack and I'm wondering why. Am I not using the right cable (I'm pretty sure it's an hdmi 1.3)? Is it a problem with the ps3? Also, I've heard the ps3 won't decode dts HD soundtracks is that true? I need help.

THanks in advance.