Attaching an object to bone dynamically

Here's the code:

 public var weapon:GameObject;
 public var weaponBone:Transform;
 
 function Start ()
 {
  // instantiate the weapon prefab
  var weaponTransform:Transform = Instantiate(weapon, weaponBone.position, weaponBone.rotation) as Transform;
 
   // make the bone a parent of the weapon
  weaponTransform.parent = weaponBone;
 }

My question is how i can set the hand bone to that "weaponBone" dynamically, because my player spawns not stands in the world already. Thanks in advance