iTween use local coordinates

Hi,
I am trying to instantiate a prefab from another obj. This instantiation needs to be relative to the parent, hence I need to use local parameters instead of Global. I dont get any errors, but the object is placed, in case below, at pos.x 10 instead of pos.obj.10

Code (csharp):

1.  
2. iTween.MoveTo(gameObject, {"x":10,"time":1,"isLocal":true});