If you don't have teh 55EA880W then you are in an unsupported area where no one may know. That is, it isn't documented to work and you have proven it as well.
When connected to other LG TV also with spdif/toslink OCF100 does not play any sound, is there any hack available?
If now then maybe next step would be rip it apart and connect to find how to integrate HDMI with speakers.

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