I played a bit around with the texture dump. My focus were the light layer. So far I discovered that game makes a simple transition from pure black to the full colored texture and vice versa to animate it. In other words the game darken the texture step by step until it reaches black and removes it step by step to get the original texture back. The question is, if we can't bring it to work by default with custom textures, couldn't we mimic the effect with a script (for each scene), which tells the driver how fast and in how many steps to add/reduce the level of black to/from these textures?