How add Ragdoll object?

I try add rag doll object in runtime but not working. if possible help me

When i made instance o group of objects rigidbody + armature + mesh lost constrains.

Any idea how use rag doll? Work only in same layer of current scene? In case rigid body with joints + armature + mesh.i wish spawn rag doll when enemy dead to same position of enemy.

Please help me