[Zope] Add a Document from an existing File

[Steffen Bergmann]

Does anybody know how to add an DTML Document with uploading the
contents from a local File on the filesystem. I need to do this in
DTML Code (or Python?) and not in the managementscreen. 
The Code:
<dtml-call "manage_addDTMLDocument('id','title','datei.html')">
only adds a Document with the contents 'datei.html'. Is there any other
option to do something like this?  

Steffen