[Unity 4.6] How to change skined mesh render after optimize game objects

I found skined mesh render's bones empty after "Optimize game objects" enabled in the model rig, so I can't rebuild bones and replace with different skeleton share the same bones hierarchy like before . These codes are work well without this thing enabled

SkinnedMeshRenderer s = go.GetComponentInChildren<SkinnedMeshRenderer>();

nbones.Clear();
bones = _src.GetComponentsInChildren<Transform>();

foreach (Transform bone in s.bones) {
foreach (Transform old in bones) {
if (old.name != bone.name) {
continue;
}
nbones.Add(old);
break;
}
}

_renderer.bones = nbones.ToArray();
_renderer.sharedMesh = s.sharedMesh;
_renderer.materials = s.materials;

 

somebody help

 

Do not optimize them, because that's one effect of optimization(and probably the only one).

 

You'd have a better chance at answers if you post in the scripting section. Additionally you will want to use code tags.