Hi Paolo, Full dislcosure, I manufacture a 24/192K DAC with HDMI input for extracting the stereo LPCM 24/96K soundtrack and agree, you can use the players built-in post processing to decode the Dolby TruHD or DTS MasterHD and output through the DAC's analog outputs. Keep the cables short, once you change from digital to analog throughput, it gets lossy fast. I've compared the HDMI vs Analog output of the player, keeping it HDMI was best to keep the digital bit-stream in its purest form coming off the disc.
Theoretically it shouldn't matter but it does. Why?
There are a few possibilities, DRM among them. The studios and record labels retain the right to down-rez the audio output to 48K from the coaxial and optical outputs when the HDMI output is enabled, keeping the HDMI for video alone might be interfering with the audio output being its best. You should compare them and see what you think.
Ciao,
Bob