[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

Code (csharp):

1.  
2. SkinnedMeshRenderer s = go.GetComponentInChildren<SkinnedMeshRenderer>();
3.  
4. nbones.Clear();
5. bones = _src.GetComponentsInChildren<Transform>();
6.  
7. foreach (Transform bone in s.bones) {
8. foreach (Transform old in bones) {
9. if (old.name != bone.name) {
10. continue;
11. }
12. nbones.Add(old);
13. break;
14. }
15. }
16.  
17. _renderer.bones = nbones.ToArray();
18. _renderer.sharedMesh = s.sharedMesh;
19. _renderer.materials = s.materials;
20.  

 

somebody help