No sound using TV Ears with Apple TV/Receiver?

Hi - I'm posting this for my dad, as we have him set up with Apple TV, Cable box, Sony Bravia (1 HDMI), ONKYO receiver 3 out 1 in (HDMI) and TV Ears Speaker. TV Ear module has audio port. http://www.tvears.com/support/Wireless-Speaker-System

Here's the setup we're using (but not getting any sound from the TV Ears speaker when viewing Apple TV):

HDMI from Sony to Onkyo Out.

Comcast Cable HDMI to Onkyo HDMI In

Apple TV to Onkyo HDMI In

TV Ears to Onkyo audio out

When we power everything up and view cable broadcasts - sound is coming from the TV Ears Speaker. When we switch inputs to Apple TV - we get picture but no sound from TV Ears speaker.

We've tried other setups but am baffled at why.

Went to the Apple store and the Genius rep. said we should get a newer tv with more HMDI inputs and run them all from there. Would that be the way to go?

Thanks in advance for any help!

Here's the TV Ears

Mike