I have checked your file and somehow I cant see a mistake -> the strange thing is, that it perfectly works when I import it into UDK so there must be something with the UE4 (probably a import setting,…) 
I’m using blender 2.70
I have checked your file and somehow I cant see a mistake -> the strange thing is, that it perfectly works when I import it into UDK so there must be something with the UE4 (probably a import setting,…)
I’m using blender 2.70