Index: src/main/java/org/apache/maven/project/ModelUtils.java
===================================================================
--- src/main/java/org/apache/maven/project/ModelUtils.java	(revision 332337)
+++ src/main/java/org/apache/maven/project/ModelUtils.java	(working copy)
@@ -64,6 +64,8 @@
             // nothing to do.
             return;
         }
+        
+        List mergedPlugins = new ArrayList();
 
         List parentPlugins = parentContainer.getPlugins();
 
@@ -99,7 +101,7 @@
                         assembledPlugin.unsetInheritanceApplied();
                     }
 
-                    assembledPlugins.put( assembledPlugin.getKey(), assembledPlugin );
+                    mergedPlugins.add(assembledPlugin);
                 }
             }
 
@@ -109,11 +111,11 @@
 
                 if ( !assembledPlugins.containsKey( childPlugin.getKey() ) )
                 {
-                    assembledPlugins.put( childPlugin.getKey(), childPlugin );
+                    mergedPlugins.add(childPlugin);
                 }
             }
 
-            childContainer.setPlugins( new ArrayList( assembledPlugins.values() ) );
+            childContainer.setPlugins(mergedPlugins);
 
             childContainer.flushPluginMap();
         }