Materials not transferred through Datasmith

I have a scene that was imported in 3dsmax as fbx files and then transferred to Unreal via Datasmith. The scene in 3dsmax shows correctly and renders all textures. However, Unreal does not compile the materials correctly and produces lots of white materials. See screenshot please and any advice is greatly appreciated.

Further to this, I saw that 3dsmax treats the materials as multi sub objects and Datasmith does not gather the associated textures of the submaterials, only provides the default color. Any ideas?