Swap Mecanim Layers in Unity 4.2

Unity currently does not support the ability to swap mecanim layers, but before version 4.2 there was a nice editor window script for doing it found here. In Unity 4.2 they changed the animator controller class, so that this script no longer works, and they still haven't added a swap feature.

Does anyone have a fix for this script? I would do it myself, but I cannot figure out what the equivalent of SetLayerType() is in the 4.2 and the state machine appears to be read only now.

Here's the script:

     using UnityEditor;
     using UnityEditorInternal;
     using UnityEngine;
      
     public class AnimatorSwapLayers : EditorWindow
     {
         private Vector2 _scrollPosition;
      
         [MenuItem("Window/Animator Swap Layers")]
         static void Init ()
         {
             AnimatorSwapLayers window = (AnimatorSwapLayers)GetWindow(typeof(AnimatorSwapLayers));
         }
      
      
         void OnSelectionChange()
         {
             Repaint();
         }
      
      
          void OnGUI()
          {
      
              if(Selection.objects.Length > 0 && Selection.objects[0] is AnimatorController)
             {
                 AnimatorController controller = (AnimatorController)Selection.objects[0];
      
                 _scrollPosition = GUILayout.BeginScrollView(_scrollPosition);
                     for (int i = 0; i < controller.GetLayerCount(); i++)
                     {
                         GUILayout.BeginHorizontal();
                             GUILayout.Label(controller.GetLayerName(i));
                                 GUILayout.FlexibleSpace();
                             if(i>0)
                             {
                                 if (GUILayout.Button("↑"))
                                 {
                                     Swap(controller, i, true);
                                 }
                             }
      
                             if (i < controller.GetLayerCount()-1)
                             {
                                 if (GUILayout.Button("↓"))
                                 {
                                     Swap(controller, i, false);
                                 }
                             }
                         GUILayout.EndHorizontal();
                             GUILayout.Space(10);
                     }
                 GUILayout.EndScrollView();
             }
             else if (Selection.objects.Length > 1)
             {
                 GUILayout.Label("Multy edit not supported");
             }
             else
             {
                 GUILayout.Label("No controller selected");
             }
         }
      
          void Swap(AnimatorController controller, int pos, bool moveUp)
          {
              int newPos = pos + (moveUp ? -1 : 1);
      
              AnimatorLayerBlendingMode blendingModeT = controller.GetLayerBlendingMode(newPos);
              bool iKPassT = controller.GetLayerIKPass(newPos);
              AvatarMask layerMaskT = controller.GetLayerMask(newPos);
              string nameT = controller.GetLayerName(newPos);
              StateMachine stateMachineT = controller.GetLayerStateMachine(newPos);
              int syncedIndexT = controller.GetLayerSyncedIndex(newPos);
              int layerTypeT = controller.GetLayerType(newPos);
      
      
              controller.SetLayerBlendingMode(newPos, controller.GetLayerBlendingMode(pos));
              controller.SetLayerIKPass(newPos, controller.GetLayerIKPass(pos));
              controller.SetLayerMask(newPos, controller.GetLayerMask(pos));
              controller.SetLayerName(newPos, controller.GetLayerName(pos));
              controller.SetLayerStateMachine(newPos, controller.GetLayerStateMachine(pos));
              controller.SetLayerSyncedIndex(newPos, controller.GetLayerSyncedIndex(pos));
              controller.SetLayerType(newPos, controller.GetLayerType(pos));
      
      
              controller.SetLayerBlendingMode(pos, blendingModeT);
              controller.SetLayerIKPass(pos, iKPassT);
              controller.SetLayerMask(pos, layerMaskT);
              controller.SetLayerName(pos, nameT);
              controller.SetLayerStateMachine(pos, stateMachineT);
              controller.SetLayerSyncedIndex(pos, syncedIndexT);
              controller.SetLayerType(pos, layerTypeT);
          }
      
     }