Decals/Billboards with multiple shadows

Hallo

We use billboards/decals to quickly add some cheap decorations to a scene e.g. a tree or a plant. These would typically be materials with a texture (JPEG, PNG etc) with an alpha channel. When we have a scene with multiple light sources, we need to be able to position the decal to show a shadow for each light. I have done this before using POVRAY, using a mesh, rotated to the light, but without it being visible, but the shadow will be visible. I will then do this for each light source. The actual decal is rotated towards the camera view. How can this be achieved in the SDK? In the image attached, image two different lights, producing shadows in these directions…

What first came to my mind was to use the old video game method - two perpendicular planes (making a cross figure) with identical (could be mirrored) tree textures. This way you don’t need to bother rotating each plane towards the camera. Here’s a screenshot (from 3ds Max) of the setup with two lights lighting the contraption.