I would try doing something like putting a light source on its own layer, set the Background color to black, "Force own texture" to true and add a Multiply effect.
Set the light source shadow color to white (have to do it in the event sheet, can't do it in the props pane.) Now your "shadows" will create a flashlight effect instead.
That doesn't get you 100% of the way there, but maybe that will give you some things to fiddle with at least.