AUDIO only from optical but not from HDMI

[macachia]

Hi there!

I have the following problem:

Magbox to TV using HDMI - audio works
Magbox to soundbar using hdmi and soundbar to TV using hdmi - audio doesn't work
Magbox to soundbar using hdmi (video) and optical out (audio) to soundbar and soundbar to TV using hdmi - audio works.

Is it possible to eliminate the optical cable and get audio from the HDMI (through the soundbar)? I tried endlessly but won't work for some reason. I tried swapping HDMI cables and HDMI ports not he soundbar but it doesn't work. Needless to say audio from other boxes like bluray and Apple TV work through the soundbar and the same hdmi cables.

Thanks in advance