Need Help with Landscaping (adding splat maps, normals to landscape material layers)

I have the same question with MattD: How to assign external splat maps to landscape? I have height map and splat maps which are exported from a Unity3D project. For the height map, I followed Epic landscape tutorials and managed to reuse it in UE4. But for the splat maps, I really don’t know how to deal with them. Anyone has a solution for this?