[Zope] FTP upload of ExtImage

[Klimovich Alexander]

Hi there!

Can anyone explain me why the following doesn't work:
I'm trying to upload ExtImage to new folder in Zope using
FTP. I have found that to tell Zope to create ExtImage instead of
Image I should write external method PUT_factory and put it 
into the folder where I'm going to store image. For uploading
ExtImage I use storbinary method of FTP object (file is representing as StringIO object). 

BUT: My PUT_factory doesn't work! Who can explain why? What am I doing wrong?

Thanks,
Alexander  Klimovich