diff --git a/OpenSim/Grid/MessagingServer/MessageService.cs b/OpenSim/Grid/MessagingServer/MessageService.cs
index 4baf51e71f..01bd9aff86 100644
--- a/OpenSim/Grid/MessagingServer/MessageService.cs
+++ b/OpenSim/Grid/MessagingServer/MessageService.cs
@@ -55,6 +55,10 @@ namespace OpenSim.Grid.MessagingServer
         //A hashtable containing lists of UUIDs keyed by UUID for fast backreferencing
         private Hashtable m_presence_BackReferences = new Hashtable();
 
+        // Hashtable containing work units that need to be processed
+        private Hashtable m_unProcessedWorkUnits = new Hashtable();
+
+
         public MessageService(LogBase log, MessageServerConfig cfg)
         {
             m_log = log;
diff --git a/OpenSim/Grid/MessagingServer/WorkUnitBase.cs b/OpenSim/Grid/MessagingServer/WorkUnitBase.cs
new file mode 100644
index 0000000000..67a535ff13
--- /dev/null
+++ b/OpenSim/Grid/MessagingServer/WorkUnitBase.cs
@@ -0,0 +1,37 @@
+/*
+* Copyright (c) Contributors, http://opensimulator.org/
+* See CONTRIBUTORS.TXT for a full list of copyright holders.
+*
+* Redistribution and use in source and binary forms, with or without
+* modification, are permitted provided that the following conditions are met:
+*     * Redistributions of source code must retain the above copyright
+*       notice, this list of conditions and the following disclaimer.
+*     * Redistributions in binary form must reproduce the above copyright
+*       notice, this list of conditions and the following disclaimer in the
+*       documentation and/or other materials provided with the distribution.
+*     * Neither the name of the OpenSim Project nor the
+*       names of its contributors may be used to endorse or promote products
+*       derived from this software without specific prior written permission.
+*
+* THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY
+* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+* DISCLAIMED. IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY
+* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+* 
+*/
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace OpenSim.Grid.MessagingServer
+{
+    public class WorkUnitBase
+    {
+    }
+}
diff --git a/OpenSim/Grid/MessagingServer/WorkUnitPresenceUpdate.cs b/OpenSim/Grid/MessagingServer/WorkUnitPresenceUpdate.cs
new file mode 100644
index 0000000000..9a729c2274
--- /dev/null
+++ b/OpenSim/Grid/MessagingServer/WorkUnitPresenceUpdate.cs
@@ -0,0 +1,37 @@
+/*
+* Copyright (c) Contributors, http://opensimulator.org/
+* See CONTRIBUTORS.TXT for a full list of copyright holders.
+*
+* Redistribution and use in source and binary forms, with or without
+* modification, are permitted provided that the following conditions are met:
+*     * Redistributions of source code must retain the above copyright
+*       notice, this list of conditions and the following disclaimer.
+*     * Redistributions in binary form must reproduce the above copyright
+*       notice, this list of conditions and the following disclaimer in the
+*       documentation and/or other materials provided with the distribution.
+*     * Neither the name of the OpenSim Project nor the
+*       names of its contributors may be used to endorse or promote products
+*       derived from this software without specific prior written permission.
+*
+* THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY
+* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+* DISCLAIMED. IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY
+* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+* 
+*/
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace OpenSim.Grid.MessagingServer
+{
+    public class WorkUnitPresenceUpdate : WorkUnitBase
+    {
+    }
+}