Got the legacy editors working and iframe implementation almost done!

src/Umbraco.Web/UI/JavaScript/JsInitialization.cs

@@ -2,6 +2,7 @@
 using System.Text.RegularExpressions;
 using Newtonsoft.Json;
 using Newtonsoft.Json.Linq;
+using Umbraco.Core.IO;
 using Umbraco.Core.Manifest;
 
 namespace Umbraco.Web.UI.JavaScript
@@ -40,7 +41,9 @@ namespace Umbraco.Web.UI.JavaScript
                 ManifestParser.MergeJArrays(umbracoInit, m.JavaScriptInitialize);
             }
 
-            return ParseMain(umbracoInit.ToString());
+            return ParseMain(
+                umbracoInit.ToString(),
+                IOHelper.ResolveUrl(SystemDirectories.Umbraco));
         }
 
         /// <summary>

src/Umbraco.Web/UI/JavaScript/JsInitialize.js

@@ -5,6 +5,8 @@
     'lib/bootstrap/js/bootstrap.js',
     'lib/underscore/underscore.js',
     'lib/umbraco/Extensions.js',
+    'lib/umbraco/NamespaceManager.js',
+    'lib/umbraco/LegacyUmbClientMgr.js',
 
     'js/app.js',
 

src/Umbraco.Web/UI/JavaScript/Main.js

@@ -3,6 +3,10 @@ yepnope({
     load: "##JsInitialize##",
 
     complete: function () {
+        
+        //we need to set the legacy UmbClientMgr path
+        UmbClientMgr.setUmbracoPath('"##UmbracoPath##"');
+
         jQuery(document).ready(function () {
             angular.bootstrap(document, ['umbraco']);
         });