animID=SurfaceLightAnim(surface, start_light, end_light, change_time);
start_light: This is the 0-1 flex light that will be given to the surface when the animation begins.
end_light: This is the 0-1 flex light that the anim will reach at the end of the animation. The end_light must be equal to or greater than the start_light or the command will be ignored.
change_time: This is the flex time in which the surface will fade from the start light to the end light. Although this time should be in seconds, the unit seems to be closer to a half-second.