The simplest way to do this would be making the _I map mask light
both colours and make the alternate diffuse 'off' textures dark. For example red is untouched and green is dark coloured, when throwing the switch the alt texture has a dark red and bright green colour.
The illumination mask would of course light both but with the darker colours in the alt diffuse textures they would appear to light on and off.
Hope this makes sense.
Since your using a community pack I have no idea if the alt texture is even there, check to see if it any different from the default and that it has the correct _I texture.
To test its working try one of the sci-fi stock switches.
Bond's metro theatre uses a shader to actually change the Illumination but I dont know that it is scriptable to prevent it constantly looping between the lit and unlit as it may use a single texture sprite map.
I cant be certain without actually testing it myself but since the sci-fi switch 2 uses both off and on _I maps it may be that the _I alt texture is selected when the alt texture changes, ON_I is used with ON_D2 and OFF_I is used with OFF_D2. It would make a lot of sense if it worked this way. Look a little closer at these particular textures and try out this switch before going any further with the one your trying to use.
Awesome! Its one of those threads.
