I have pretty much got into the same trouble with the right foot, and have resorted to using .dae export and using AutoDesk’s FBX converter (you can get that for free).
Here is how it goes:
- Open “SK_UE4_Mannequinn_273.blend”
- Select all under object mode, Press “N” for Transform tab, and set scale for X, Y, and Z to 1.00 (from 0.01)
- Select all under object mode, Rotate everything such that Z points Up, Y points Backwards, and X points Left
- Export under “.dae”, using operator presets
- Use AutoDesk FBX converter to convert to FBX2013. Be sure to select Binary under “FBX Save Mode”, and also check “embed media”