nick , while watching blurays , you should see "dolby digital" , "dolby true hd" , or "dts mas audio" depending on the audio on the disc , but , you have to go into the bluray disc settings with most blurays , and select the optimium soundtrack available , as most default to dolby didital...
also , id check the settings on your bdp360 , i have a feeling that it may be decoding the audio , the settings should be
audio output priority ........ hdmi
audio(hdmi).................auto
bd
audio setting...........direct
audio att...................off
dolby
digital..........dolby digital
dts................dts
48khz/96khz
pcm...............96khz
audio drc.................widerange...
downmix..............normal..
apply these to your sony , and the amp will then definately be doing the decoding , if it isnt already ...