diff --git a/tracking/README.txt b/tracking/README.txt
index c5e23fa..9138188 100644
--- a/tracking/README.txt
+++ b/tracking/README.txt
@@ -56,13 +56,13 @@ Instead of creating a new track object for each call one can also replace
 an existing one (if present). The replaced entry is always the last one
 for a given set of keys.
 
-  >>> tracks.saveUserTrack('a001', 0, 'u1', {'somekey': 'newvalue2'}, replace=True)
+  >>> tracks.saveUserTrack('a001', 0, 'u1', {'somekey': 'newvalue2'}, update=True)
   '0000003'
   >>> t3 = tracks.getUserTracks('a001', 0, 'u1')
   >>> [t.data for t in t3]
   [{'somekey': 'somevalue'}, {'somekey': 'newvalue2'}]
 
-  >>> tracks.saveUserTrack('a001', 0, 'u2', {'somekey': 'user2'}, replace=True)
+  >>> tracks.saveUserTrack('a001', 0, 'u2', {'somekey': 'user2'}, update=True)
   '0000004'
   >>> t4 = tracks.getUserTracks('a001', 0, 'u2')
   >>> [t.data for t in t4]
@@ -124,7 +124,3 @@ We can also mark earlier runs by stopping them.
   >>> tracks.getRun(runId=2)
   <Run 2, ..., ..., True>
 
-
-Fin de partie
-=============
-
diff --git a/tracking/btree.py b/tracking/btree.py
index fbd505b..d2560c6 100644
--- a/tracking/btree.py
+++ b/tracking/btree.py
@@ -100,7 +100,7 @@ class TrackingStorage(BTreeContainer):
             return self.runs.get(runId)
         return None
 
-    def saveUserTrack(self, taskId, runId, userName, data, replace=False):
+    def saveUserTrack(self, taskId, runId, userName, data, update=False):
         if not runId:
             runId = self.currentRuns.get(taskId) or self.startRun(taskId)
         run = self.getRun(runId=runId)
@@ -108,17 +108,19 @@ class TrackingStorage(BTreeContainer):
             raise ValueError('Invalid run: %i.' % runId)
         run.end = getTimeStamp()
         trackNum = 0
-        if replace:
+        if update:
             track = self.getLastUserTrack(taskId, runId, userName)
             if track:
                 trackId = str(track.__name__)
                 trackNum = int(trackId)
-                del self[trackId]
+                track.data.update(data)
+                self.indexTrack(trackNum, track)
+                return trackId
         if not trackNum:
             self.trackNum += 1
             trackNum = self.trackNum
             trackId = self.idFromNum(trackNum)
-        track = Track(taskId, runId, userName, getTimeStamp(), data)
+        track = Track(taskId, runId, userName, data)
         self[trackId] = track
         self.indexTrack(trackNum, track)
         return trackId
@@ -183,11 +185,15 @@ class Track(Persistent):
     def metadata(self):
         return dict((attr, getattr(self, attr)) for attr in self.metadata_attributes)
 
-    def __init__(self, taskId, runId, userName, timeStamp, data={}):
+    def __init__(self, taskId, runId, userName, data={}):
         self.taskId = taskId
         self.runId = runId
         self.userName = userName
-        self.timeStamp = timeStamp
+        self.timeStamp = getTimeStamp()
+        self.data = data
+
+    def update(self, data):
+        self.timeStamp = getTimeStamp()
         self.data = data
 
     def __repr__(self):
diff --git a/tracking/interfaces.py b/tracking/interfaces.py
index 8d0fd4a..35ec29e 100644
--- a/tracking/interfaces.py
+++ b/tracking/interfaces.py
@@ -72,11 +72,11 @@ class ITrackingStorage(Interface):
             current run of the task.
         """
 
-    def saveUserTrack(taskId, runId, userName, data, replace=False):
+    def saveUserTrack(taskId, runId, userName, data, update=False):
         """ Save the data given (typically a mapping object) to the user track
             corresponding to the user name, task id, and run id given.
             If the runId is 0 use the task's current run.
-            If the ``replace`` flag is set, the new track replaces the last
+            If the ``update`` flag is set, the new track updates the last
             one for the given set of keys.
             Return the new track item's id.
         """