http://cg.tutsplus.com/tutorials/3d-art/alter-your-lighting-information-post-render-using-multilight-in-maxwell-studio/

In this tutorial we will take a look at a few of the incredibly efficient features of Maxwell Studio, including Multilight, the revolutionary tool that allows you to alter lighting post render. We will also cover several terms that are often misunderstood, and a few other things that will allow you to get believable results from your renders.