Index: manipulators.py
===================================================================
--- manipulators.py	(revision 3463)
+++ manipulators.py	(working copy)
@@ -180,7 +180,7 @@
                             param = getattr(new_object, related.field.rel.field_name)
                         elif (not self.change) and isinstance(f, AutoField):
                             param = None
-                        elif self.change and (isinstance(f, FileField) or not child_follow.get(f.name, None)):
+                        elif self.change and (isinstance(f, FileField) or not child_follow.get(f.name, None) or not f.editable):
                             if old_rel_obj:
                                 param = getattr(old_rel_obj, f.column)
                             else: