Please don't ask me how I did this one.
It was a result from two hours "gefreubel".
A stroke of luck I think.
I've used only 4 watercolour-textures (blendingmode = multiply & linear burn) and played a long time with the render filter to recive this light effect and other tools. Pffffjoei !
Credits for the free watercolor pack... HERE. (mediamilitia.com)