For some dumb reason they still haven't fixed this dumb bug...
mount -o remount,rw /flash
and nano /flash/config.txt
hdmi_force_edid_audio=1
mount -o remount,ro /flash
and reboot
(If you have your SD card handy you can also just plug that into your PC and you will find config.txt in the root of it, just add hdmi_force_edid_audio=1
to the bottom of that and save and it will have the same effect.)
And that's it. Now I get Stereo, AC3 5.1 and DTS 5.1 over optical into my soundbar from my Pi 2 running PMP 1.1.1.
Or you could just use Rasplex instead...
Footnote: for some dumb reason I couldn't use codeblocks. It just refused to, even though the preview in Atom was fine. I'm thinking it's Parsedown's fault.