Scaled already animated armature and mesh .

when i scale the armature it scales the mesh too and works great, but when i apply the scale to the armature the animation is corrupted :

If lets say the animation is : move 5 unit from a to b .
I scale the armature and it keeps it proportions, but after i apply scale, it looks like the animation went back to it’s initial value which is good for the original size of the armature but not the new size .
So it looks like the animation is moving 0.5 from a to b instead of 5 from a to b .

How can i fix that ?

Anyone ?..