There is probably a coax or TOSLINK connection coming from the TV which will carry the audio to an appropriate input on your HT system. And/or you might also look carefully at your TV's manual and see if a configuration setting is amiss...
Check your PCM and Dolby Digital in and out settings for all of your gear. I'm not familiar with your equipment, but something may set for PCM 2 channel, and may need to be set for Dolby Digital. If you make any changes, write it down so you can go back it doesn't work. Also, make only one change at a time when trying, and double check your manuals.
Hi Jdoris, the PCM stands for Pulse Code Modulation. Some TVs and cable boxes have different bit rate settings that even will put out a regular two channel signal that is compatible with a standard CD player's D/A converters. Then some other setting have a higher bit-rate that requires a Dolby Digital decoder for anything to happen.
On this Panasonic TV, page 176 in the Pdf manual talks about "default speaker" settings. Then on pages 21, 150, there are other settings. I don't know if any of these would do you any good. I wish I was more up to date on this TV audio. I have problems at times too. I'm used to regular CD player outputs, etc. The answer may be in the manual somewhere, but there's probably not an answer that will guarantee it will be compatible. I hope you can get it worked out.