I live in charleston, wv and my local cbs station wowk tv 13 added a hd feed so they are now in hd via charter or ota. i get all the other locals in hd via ota. like on nbc, when law and order comes on, i see hd and my receiver clicks on dolby digital for dolby digital 5.1 sound. but with the cbs hd when i watched this new show the unit, it was in hd and it said it was in hd 5.1 sound but my sound was the same and didnt go into 5.1 dolby digital on my receiver. can someone tell me why that is?