PS3 +ONKYO SR605 questions

[slickkeng]

Hi I just got an onkyo sr605 receiver to go with my PS3 via HDMI and it is awesome. I did have a question however, I have a 7.1 setup and I know the PS3 is capable of 7.1 pcmm but on my SD-DVD's with dolby digital EX or DTS ES which are both 6.1, my back rear channels are not untilized. I think this might be the PS3's problem and inability to internally decode these codecs right? I know its possible to do over bitstream, but via lpcm the rear channels are lost. Also, on 7.1 system, when watching a 5.1 source are the rear channels suppose to be silent as well, I only hear sound from the center, fronts and sides (shouldn't the sides be silent and the rears active? Sorry for newbie questions, but I'm new to this whole home theater audio stuff!!!! Any help would be great. Oh and by the way, I hear that the PS3 is getting internal decoding of DTS-HD MA in a future firmware upgrade before xmas (its still a rumour but I read it on Hidef Digest that DTS people are working with Sony on this) which means we can finnaly hear FOX titles in full HD audio glory. I also hope they give us options for Dolby True HD and DTS-HD MA via bitsream as well for processing through our receivers. Thanks for any help possible!