[Zope] changing LocalFS content type

I have some data that was uploaded to a LocalFS (Local File System) dir and the type of the code was incorrectly specified as application/octet-stream when it should be text/plain. I went into the manager interface and changed the 'Content Type' field and got no errors, but when I go back and look I see that it is still application/octet-stream. Is this a bug in bug in LocalFS? Does anyone know how if it is possible to change the content type of an LocalFS file? The file was uploaded to the zope server LocalFS dir using some client java code that incorrectly specified the content type. Thanks, John Hunter LocalFS-0.10.1 Zope 2.5.1b1 (source release, python 2.1, linux2), python 2.1.3, linux2)