diff --git a/source/java/org/alfresco/repo/action/ActionTrackingServiceImpl.java b/source/java/org/alfresco/repo/action/ActionTrackingServiceImpl.java
index f9a7b01b93..db325c3ed3 100644
--- a/source/java/org/alfresco/repo/action/ActionTrackingServiceImpl.java
+++ b/source/java/org/alfresco/repo/action/ActionTrackingServiceImpl.java
@@ -64,6 +64,7 @@ public class ActionTrackingServiceImpl implements ActionTrackingService
     *  quickest and easiest way.
     */
    private short nextExecutionId = 1;
+   private short wrapExecutionIdAfter = Short.MAX_VALUE/2;
    
    /** How we separate bits of the cache key */
    private static final char cacheKeyPartSeparator = '=';
@@ -106,10 +107,18 @@ public class ActionTrackingServiceImpl implements ActionTrackingService
    
    public void recordActionPending(Action action) 
    {
-      ((ActionImpl)action).setExecutionStatus(ActionStatus.Pending);
+      recordActionPending((ActionImpl)action);
+   }
+   public void recordActionPending(ActionImpl action)
+   {
+      action.setExecutionStatus(ActionStatus.Pending);
    }
    
    public void recordActionComplete(Action action) 
+   {
+      recordActionComplete((ActionImpl)action);
+   }
+   private void recordActionComplete(ActionImpl action)
    {
       if (logger.isDebugEnabled() == true)
       {
@@ -117,9 +126,9 @@ public class ActionTrackingServiceImpl implements ActionTrackingService
       }
       
       // Mark it as having worked
-      ((ActionImpl)action).setExecutionEndDate(new Date());
-      ((ActionImpl)action).setExecutionStatus(ActionStatus.Completed);
-      ((ActionImpl)action).setExecutionFailureMessage(null);
+      action.setExecutionEndDate(new Date());
+      action.setExecutionStatus(ActionStatus.Completed);
+      action.setExecutionFailureMessage(null);
       if(action.getNodeRef() != null)
       {
          runtimeActionService.saveActionImpl(action.getNodeRef(), action);
@@ -131,6 +140,10 @@ public class ActionTrackingServiceImpl implements ActionTrackingService
    }
 
    public void recordActionExecuting(Action action) 
+   {
+      recordActionExecuting((ActionImpl)action);
+   }
+   private void recordActionExecuting(ActionImpl action)
    {
       if (logger.isDebugEnabled() == true)
       {
@@ -138,14 +151,34 @@ public class ActionTrackingServiceImpl implements ActionTrackingService
       }
       
       // Mark the action as starting
-      ((ActionImpl)action).setExecutionStartDate(new Date());
-      ((ActionImpl)action).setExecutionStatus(ActionStatus.Running);
+      action.setExecutionStartDate(new Date());
+      action.setExecutionStatus(ActionStatus.Running);
       
-      // TODO assign it a (unique) execution ID
+      // Assign it a (unique) execution ID
       // (Keep checking to see if the key is used as we
       //  increase nextExecutionId until it isn't)
-      ((ActionImpl)action).setExecutionInstance(nextExecutionId++); // TODO
-      String key = generateCacheKey(action);
+      String key = null;
+      boolean assigned = false;
+      while(!assigned) {
+         // Try
+         action.setExecutionInstance(nextExecutionId++);
+         key = generateCacheKey(action);
+         
+         // Is it ok?
+         if(executingActionsCache.get(key) == null) {
+            assigned = true;
+         }
+         
+         // Do we need to wrap?
+         // (Wrap before absolutely needed, makes things simpler)
+         if(nextExecutionId > wrapExecutionIdAfter) {
+            synchronized (this) {
+               while(nextExecutionId > wrapExecutionIdAfter) {
+                  nextExecutionId -= wrapExecutionIdAfter;
+               }
+            }
+         }
+      }
       
       // Put it into the cache
       ExecutionDetails details = buildExecutionDetails(action);
diff --git a/source/java/org/alfresco/repo/action/ActionTrackingServiceImplTest.java b/source/java/org/alfresco/repo/action/ActionTrackingServiceImplTest.java
index 49b6f0d724..2d59f42415 100644
--- a/source/java/org/alfresco/repo/action/ActionTrackingServiceImplTest.java
+++ b/source/java/org/alfresco/repo/action/ActionTrackingServiceImplTest.java
@@ -175,9 +175,22 @@ public class ActionTrackingServiceImplTest extends TestCase
     }
     
     /** Running an action gives it an execution ID */
-    public void testExecutionInstanceAssignment()
+    public void testExecutionInstanceAssignment() throws Exception
     {
-       // TODO
+       ActionImpl action = (ActionImpl)createWorkingSleepAction("1234");
+       assertEquals(-1, action.getExecutionInstance());
+       
+       // Have it run, will get the ID of 1
+       actionTrackingService.recordActionExecuting(action);
+       assertEquals(1, action.getExecutionInstance());
+       
+       // And again, gets 2
+       actionTrackingService.recordActionExecuting(action);
+       assertEquals(2, action.getExecutionInstance());
+       
+       // And again, gets 3
+       actionTrackingService.recordActionExecuting(action);
+       assertEquals(3, action.getExecutionInstance());
     }
     
     /** 
@@ -489,8 +502,71 @@ public class ActionTrackingServiceImplTest extends TestCase
        assertEquals(
              1, actionTrackingService.getExecutingActions(moveAction).size()
        );
+
        
-       // TODO Multiple actions of the same instance
+       // Check for multiple instances of the same action
+       runtimeActionService.saveActionImpl(nodeRef, sleepAction1);
+       ((ActionTrackingServiceImpl)actionTrackingService).resetNextExecutionId();
+       
+       ActionImpl sa11 = (ActionImpl)runtimeActionService.createAction(nodeRef);
+       ActionImpl sa12 = (ActionImpl)runtimeActionService.createAction(nodeRef);
+       ActionImpl sa13 = (ActionImpl)runtimeActionService.createAction(nodeRef);
+       sa11 = new ActionImpl(sa11, SleepActionExecuter.NAME);
+       sa12 = new ActionImpl(sa12, SleepActionExecuter.NAME);
+       sa13 = new ActionImpl(sa13, SleepActionExecuter.NAME);
+       
+       actionTrackingService.recordActionExecuting(sa11);
+       actionTrackingService.recordActionExecuting(sa12);
+       actionTrackingService.recordActionExecuting(sa13);
+       assertEquals(1, sa11.getExecutionInstance());
+       assertEquals(2, sa12.getExecutionInstance());
+       assertEquals(3, sa13.getExecutionInstance());
+       
+       assertEquals(
+             4, actionTrackingService.getAllExecutingActions().size()
+       );
+       assertEquals(
+             0, actionTrackingService.getExecutingActions("test").size()
+       );
+       assertEquals(
+             3, actionTrackingService.getExecutingActions(SleepActionExecuter.NAME).size()
+       );
+       assertEquals(
+             1, actionTrackingService.getExecutingActions(moveAction).size()
+       );
+       assertEquals(
+             3, actionTrackingService.getExecutingActions(sa11).size()
+       );
+       assertEquals(
+             3, actionTrackingService.getExecutingActions(sa12).size()
+       );
+       assertEquals(
+             3, actionTrackingService.getExecutingActions(sa13).size()
+       );
+
+       
+       actionTrackingService.recordActionComplete(sa13);
+       actionTrackingService.recordActionComplete(moveAction);
+       
+       
+       assertEquals(
+             2, actionTrackingService.getAllExecutingActions().size()
+       );
+       assertEquals(
+             0, actionTrackingService.getExecutingActions("test").size()
+       );
+       assertEquals(
+             2, actionTrackingService.getExecutingActions(SleepActionExecuter.NAME).size()
+       );
+       assertEquals(
+             2, actionTrackingService.getExecutingActions(sa11).size()
+       );
+       assertEquals(
+             2, actionTrackingService.getExecutingActions(sa12).size()
+       );
+       assertEquals(
+             2, actionTrackingService.getExecutingActions(sa13).size() // Others still going
+       );
     }
     
     /** Cancel related */