diff --git a/rattail_harvest/harvest/importing/model.py b/rattail_harvest/harvest/importing/model.py
index 47e85de..582c159 100644
--- a/rattail_harvest/harvest/importing/model.py
+++ b/rattail_harvest/harvest/importing/model.py
@@ -40,7 +40,9 @@ class TimeEntryImporter(ToHarvest):
     Harvest time entry data importer.
     """
     model_name = 'TimeEntry'
+    key = 'id'
     supported_fields = [
+        'id',
         'user_id',
         'project_id',
         'task_id',
@@ -69,6 +71,7 @@ class TimeEntryImporter(ToHarvest):
 
     def normalize_local_object(self, entry):
         data = {
+            'id': entry['id'],
             'project_id': entry['project']['id'],
             'task_id': entry['task']['id'],
             'spent_date': entry['spent_date'],
@@ -83,6 +86,14 @@ class TimeEntryImporter(ToHarvest):
 
         return data
 
+    def get_next_harvest_id(self):
+        if hasattr(self, 'next_harvest_id'):
+            next_id = self.next_harvest_id
+        else:
+            next_id = 1
+        self.next_harvest_id = next_id + 1
+        return -next_id
+
     def create_object(self, key, host_data):
         if self.dry_run:
             # mock out return value