if you had to guess would you say that your old system and new system both sound like they are stereo (left channel, right channel) but not surround sound (3.1, 5.1, 7.1, etc) ? in regards to hd-tuner input signal.
you said that you get 5.1 surround sound when using the disk player. this confirms that the speaker sets were working absolutely fine.
sounds like the problem is either in how you are hooking up the system or in your hd tuner. you are probably getting only a stereo signal currently.
in total what outputs are on the HD-Tuner box? (hdmi? component?)
what inputs are on the speaker receiver? (typically hdmi, coax, component, etc)
you have the speaker receiver connected in this order? HDT->REC->TV
does surround sound even come with your satalite signal? if you aren't even getting hdsound from the source then you cannot expect it from your speakers.
again i'll reitterate: if you dont have a surround sound source then you won't ever get true surround sound. period. you can get all the speakers to play sound but it is not the same thing.