Correct me if I’m wrong but the lighting of models and the map itself are baked into it when compiled. You would need some serious changes to the source engine in order to get this to work properly. That or completely custom models and maps.
It’d take some map logic to fake a day-to-night system. Even then; it would be very expensive, file size intensive, and cause graphical bugs in-game.
But if you can do this all with lua; that’d be pretty fantastic.
[editline]16th June 2015[/editline]
A way that I can think of off the top of my head is not utilizing prop_statics and instead use prop_dynamics. The file size will be very heavy and it’ll take extra optimization; but this may help you get closer to your goal.
Cubemaps will have to be disabled, or else you’ll get funky reflections.