I have a PANASONIC home theater sound system.
If I play a DVD, the sound from the system eminates from the 5 speakers but when a TV program is broadcast only 2 of the speakers are active. Is this normal?
I have a 5.1 system too, sound from Sky etc is only in stereo, the new HD boxes will broadcast in 5.1 but for now all is stereo.
When using your system you could also try switching to 'surround' as opposed to 'stereo' - you might get the odd atmospheric sound in the rear speakers but not much when it's just stereo.