Instantiate as child of target object

You can find the object "summonPoint" by name with transform.Find, then child the new object to it - like this:

 ...
 var summon = transform.Find("Torso/LegPoint/summonPoint");
 newObject.transform.parent = summon;
 ...

You must specify the correct path, or the object will not be found. If you don't want to worry about the exact path, add the function below to your script - this function can find a transform by name down in the hierarchy:

 static function FindInChildren(name: String, tf: Transform): Transform {
     if (!tf.gameObject.active) return null;
     var tgt = tf.Find(name);
     if (!tgt) for (var child in tf){
         tgt = FindInChildren(name, child);
         if (tgt) return tgt;
     }
     return tgt;
 }

Find the "summonPoint" and make it the new object's parent this way:

 ...
 var summon = FindInChildren("summonPoint", transform);
 newObject.transform.parent = summon;
 ...