How can I use CreateInstance with custom constructors:

using UnityEngine;
using System.Collections;

public class Example : ScriptableObject
{
  // don't allow a call to the default constructor
  private Example () {}

  // how do I use CreateInstance to create an instance of 
  // Example that calls this constructor
  public Example (string message)
  {
    Debug.Log ("It worked!! " + message);
  }
} 

Are there any examples of this anywhere?