Soundbar control from Virgin remote

My setup is simple Virgin 360 Tivo box > HDMI > LG TV >HDMI eARC >D60

Everything works except for volume control.  I cannot program my Virgin remote because Ultimea is not listed in the connectable devices list.  CEC is switched on on the TV but that makes no difference (I don't think it would in any case as the source of the sound is not the TV).  Does anyone else have a similar setup with an answer?  Support line says things like 'make sure CEC is on', 'Use an HDMI cable', 'is it switched on', the usual helpful stuff which a cat could do!