On page 11 of the operating manual (Page 15 of the pdf) there is a cable that has 3.5mm on one end and analogue audio (red/white) at the other end. If you get a cable like this but insert it in the headphone out jack, that may work for you. Make sure the cable is a "stereo" cable at the "jack end". Some are mono and the jack is slightly different.
I don't know if the headphone jack becomes active as soon as you insert the cable, or if you need to activate it in the audio user settings of the TV. With most TVs the TV speakers turn off as you insert the headphones and it's active.
This may do the trick: Cost may be slightly higher in brick & mortar stores. Once connected, if you want to use headphones, you should be able to use the jack on the Kenwood.
There's also a digital coax to analogue audio converter, but some of these only work with PCM and not Dolby Digital. You'll need to configure the audio output on the TV to PCM instead of RAW if you get one of these. This is covered in the operating manual - search for PCM.