This is an odd thing. After some research and messing around, I discovered how to set up control the volume on my Onkyo receiver (an older model TX-SR575) using the remote for my 43" Frame (QN43LS03BAFXZA). However, it is only seems to be working when in the Setting part of the TV menu. When I'm at the home menu or watching a television, the volume does nothing. It pops up the in screen message showing it is connected to optical, but the receiver volume does not change. As soon as I go back to the settings section on the TV, the volume behaves as expected.
Details on set-up: The sound is being pushed via an optical cable since the HDMIs are not ARC. I connected HDMI 4 on the TV to the HDMI output on the Onkyo. Interestingly, when I go through the Universal Remote setup I get a message telling me there is no signal when I select the given HDMI. However, when I go through the set-up it works (though it does take until the 4th try until it finds the approach that works).
Anyway, the problem doesn't seem to be in the devices properly communicating, it is just not doing it from a TV location that is useful.