diff -r 3c6ce0a5ab2c -r 235a9ec83b95 ConfigTreeNode.py
--- a/ConfigTreeNode.py	Thu Nov 15 22:57:55 2012 +0100
+++ b/ConfigTreeNode.py	Thu Nov 15 23:00:53 2012 +0100
@@ -195,6 +195,18 @@
         shutil.copytree(src_CTNPath, self.CTNPath)
         return True
 
+    def CTNGlobalInstances(self):
+        """
+        @return: [(instance_name, instance_type),...]
+        """
+        return []
+    
+    def _GlobalInstances(self):
+        instances = self.CTNGlobalInstances()
+        for CTNChild in self.IECSortedChildren():
+            instances.extend(CTNChild._GlobalInstances())
+        return instances
+    
     def CTNGenerate_C(self, buildpath, locations):
         """
         Generate C code