Can I render backfaces on vertex lit terrain detail meshes?

When specifying a mesh as a "detail" mesh in unity's terrain editor, the engine seems to ignore the shader applied to the original model (nature-soft-occ-leaves). If I select it to be a "grass" object it will render both front and back faces of the mesh, but it looks flat and pretty terrible. If it's selected as a detail object, it will only render front faces. How can I change this detail mesh setting/ shader to NOT cull backfaces?

Also, will these detail objects cast shadows? It doesn't appear that they will by default. Is there any way to make them do so? Or can/will they be included in a lightmapping bake? Are these detail objects 'static' by default?