Unity iPhone does not detect mouse clicks as taps

I am using Unity iPhone version 1.5.1f2. I am trying to detect taps on 3D objects using rays. On the simulator I am using mouseclicks as taps. However, Unity does not catch the mouseclicks. Here is the code I am using, adapted from code I found online:

 using UnityEngine;
 using System.Collections;
 
 public class multitouch_response : MonoBehaviour
 {
 
     // Use this for initialization
     void Start ()
     {
         
     }
     
     public int tc = 0;
     
     void Update () {
         // Code for OnMouseDown in the iPhone. Unquote to test.
         RaycastHit hit = new RaycastHit();
         Debug.Log("touchCount " + iPhoneInput.touchCount + " taps " + tc);
 
         for (int i = 0; i < iPhoneInput.touchCount; ++i) {
             Debug.Log("Touches");
 
             if (iPhoneInput.GetTouch(i).phase.Equals(iPhoneTouchPhase.Began)) {
                 Debug.Log("Touch began");
 
                 // Construct a ray from the current touch coordinates
                 Ray ray = Camera.main.ScreenPointToRay(iPhoneInput.GetTouch(i).position);
 
                 if (Physics.Raycast(ray, out hit)) {
                     hit.transform.gameObject.SendMessage("OnMouseDown");
                 }
             }
            }
     }
 
     public void OnMouseDown () {
         tc++;
     }
 }

The only debug information produced is:

touchCount 0 taps 0

So this means the code is not picking up any touches.

Can someone help explain what I'm doing wrong here?

Much appreciated, Eric