Renoir style light effects

Earth Balm

I'm currently using both iray and reality / Luxrender to simultaeneously render the same image and using hdri lighting to light the scene. Many of my hdr images have dappled light coming between leaves on trees, very Renoir like - see attached image. My question is: Is there any way that I can use a mesh or infinite light and a silhouette to mimic the effect on the skin of my figures? 

Thanks for responses in advance,

Dale