[Problem] importing human character animation with weapon/item sockets

Hi

I have a character rig with two extra bones for weapon sockets. The problem is weapon sockets aren't animated in Unity. I've got them working at some point but I cannot recall what I was doing differently. I've checked the rig with socket bones being parented to the root bone as well as not being parented at all.

Here is view from original blender file:


Here is view from blender when imported .fbx file:


And here is view from Unity Editor:


Here are source files and the test project if someone wants to check it:
https://drive.google.com/open?id=0B6Tp6DGuHBIlQzVIV2ZOZ3JUT2M

Do someone have a clue what should I check or change in order to make it work?

 

I've managed to make the animation work by doing the same thing multiple times. Or at least I cannot spot any difference in how animations are imported.

You can see 2 skinned meshes - one with all animations working and second with only one of the 2 animation working. If anyone can point where the difference with importing is, I'll be glad.

Here's updated project:
https://drive.google.com/open?id=0B6Tp6DGuHBIlVTFSTVlXZ1FxRFU