--- a/src/hdalab/fields.py	Fri Nov 14 17:06:02 2014 +0100
+++ b/src/hdalab/fields.py	Sun Nov 16 18:09:42 2014 +0100
@@ -7,9 +7,10 @@
 
 @author: ymh
 '''
+from django.core.exceptions import ObjectDoesNotExist
 from django.db import models
 from django.db.models import fields as django_fields
-from django.core.exceptions import ObjectDoesNotExist
+from south.modelsinspector import add_introspection_rules
 
 
 class OneToOneField(models.OneToOneField):    
@@ -38,4 +39,14 @@
             setattr(instance, self.cache_name, value)
             if value is not None:
                 setattr(value, self.related.field.get_cache_name(), instance)
-            return value
\ No newline at end of file
+            return value
+        
+add_introspection_rules([
+    (
+        [OneToOneField],
+        [],         # Positional arguments (not used)
+        {           # Keyword argument
+            "related_default": ["related_default", {"default": None}],
+        },
+    ),
+], ["^hdalab\.fields\.OneToOneField"])
\ No newline at end of file