@Maru - I can also confirm OP's original problem: that the "Occlude other Lights" settings affects which layers in lightmixer the light-object appears in.
I've found, that if a LightMtl with Emit ON occlude other lights and is directly visible, then part of the light will be seen in the "Rest" layer. But if the object is set to not casting shadows (in the object properties) then there's no visible parts in the "Rest" layer.
Hope this helps nailing the cause of these problems.
Regards
BTW - Used maxdesign2014 and Corona 1.6RC3
