Ashleys example and tutorial are nice but "problem" is still here and will remain here because current editor was never build to handle that kind of things.
Besides that it's not a solution to have more than 1 light in the layout but it's more like a someone said earlier a hack to make it work just to prove it can be done.
1 light per 1 layer is idiotic and even more limiting. Forget about bigger layouts with dozens of lights or even having dozens of levels with more than 3 lights on each (well, unless you want to spend half of your life setting and managing it up,..), forget about spawning random objects that emit lights (can't create layers at runtime)...
And there's still a Normal map textures issue - one of the main things in that post - which obviously don't work with more than 1 light source after all this years...
so yeah. C5 maybe.