Hi,
with a special PUC it's possible to use all sources from the LG TV with sound from BS3 and control the LG TV with Beo4.
Speakers all connected to BS3. Coax converter from LG TV to BS3 for sound.
Sound configuration from LG TV to optical.
Display1 from BS3 to LG HDMI1.
IR 1+2 from BS3 connect to LG TV and PUC's for controlling and power TV on/off from BS3. (Adapter needed)
Internal TV from the BS3 disable, and you could use the LG TV with Beo4 by using TV.
In my setup i'm using a Samsung TV with similar configuration and PUC for Samsung 4K TV.
Example, yellow key from Beo4 = source from Samsung TV.
Switching to HDMI1 from LG offers all settings and sources from BS3.
And motirized Stand testet with an motorized Stand from Beovision-7.
It works.
Regards