[Zope] Add a Document from an existing File

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