Child problem in animation

Hi dear users,i'm having a very anoying problem with a fbx model that i animated in blender.There is the model in blender:

As you see,the the eyes and the mouth follows the body/the parent mesh when i play the animation in blender,when i export the model in fbx and import in unity there's no problem,textures,animations are imported successfully.BUT that's what happend with the eyes and mouth meshes when the animation plays in unity:

Only the parent moves correct and $$anonymous$$s c$$anonymous$$ld meshes stay stopped and separated from $$anonymous$$m.I tried parenting the eyes and teeth with the head bone but happends the same.I wasted a lot of time trying to solve t$$anonymous$$s problem and i'm hopeless,help please.

Ops and sorry for my bad english ;P