diff --git a/calendar/base/src/calItemBase.js.pre b/calendar/base/src/calItemBase.js.pre
index 453684193a84..0f43288ff198 100644
--- a/calendar/base/src/calItemBase.js.pre
+++ b/calendar/base/src/calItemBase.js.pre
@@ -76,11 +76,13 @@ calItemBase.prototype = {
         this.mCreationDate = createCalDateTime();
         this.mAlarmTime = createCalDateTime();
 
+        this.mProperties = Components.classes["@mozilla.org/hash-property-bag;1"].
+                           createInstance(Components.interfaces.nsIWritablePropertyBag);
+
         // fix me
         this.mRecurrenceInfo = null;
         this.mAttachments = null;
         this.mContacts = null;
-        this.mProperties = null;
     },
 
     // for subclasses to use; copies the ItemBase's values
@@ -141,6 +143,9 @@ calItemBase.prototype = {
 
 function calItemOccurrence () {
     this.wrappedJSObject = this;
+
+    this.occurrenceStartDate = createCalDateTime();
+    this.occurrenceEndDate = createCalDateTime();
 }
 
 calItemOccurrence.prototype = {
diff --git a/calendar/base/src/calItemModule.js b/calendar/base/src/calItemModule.js
index 8e036f2bbded..cef230d1725a 100644
--- a/calendar/base/src/calItemModule.js
+++ b/calendar/base/src/calItemModule.js
@@ -44,6 +44,9 @@ var calItemModule = {
     mTodoCID: Components.ID("{7af51168-6abe-4a31-984d-6f8a3989212d}"),
     mTodoContractId: "@mozilla.org/calendar/todo;1",
 
+    mItemOccurrenceCID: Components.ID("{bad672b3-30b8-4ecd-8075-7153313d1f2c}"),
+    mItemOccurrenceContractId: "@mozilla.org/calendar/item-occurrence;1",
+
     mScriptsLoaded: false,
     loadScripts: function () {
         if (this.mScriptsLoaded)
@@ -80,8 +83,8 @@ var calItemModule = {
     registerSelf: function (compMgr, fileSpec, location, type) {
         compMgr = compMgr.QueryInterface(Components.interfaces.nsIComponentRegistrar);
 
-        var cids = [ this.mEventCID, this.mTodoCID ];
-        var contractids = [ this.mEventContractId, this.mTodoContractId ];
+        var cids = [ this.mEventCID, this.mTodoCID, this.mItemOccurrenceCID ];
+        var contractids = [ this.mEventContractId, this.mTodoContractId, this.mItemOccurrenceContractId ];
 
         for (var i = 0; i < cids.length; i++) {
             dump ("calItemModule: registering " + contractids[i] + "\n");
@@ -107,6 +110,9 @@ var calItemModule = {
         if (cid.equals(this.mTodoCID))
             return this.mTodoFactory;
 
+        if (cid.equals(this.mItemOccurrenceCID))
+            return this.mItemOccurrenceFactory;
+
         throw Components.results.NS_ERROR_NO_INTERFACE;
     },
 
@@ -140,6 +146,21 @@ var calItemModule = {
         }
     },
 
+    mItemOccurrenceFactory: {
+        QueryInterface: function (aIID) {
+            if (!aIID.equals(Components.interfaces.nsISupports) &&
+                !aIID.equals(Components.interfaces.nsIFactory))
+                throw Components.results.NS_ERROR_NO_INTERFACE;
+            return this;
+        },
+
+        createInstance: function (outer, iid) {
+            if (outer != null)
+                throw Components.results.NS_ERROR_NO_AGGREGATION;
+            return (new calItemOccurrence()).QueryInterface(iid);
+        }
+    },
+
     canUnload: function(compMgr) {
         return true;
     }