[Zope] How do I set the Title property of a File object from a DTML method

[magnus@websys.no]

I have some of my own ZClass objects that may contain other ZClass
objects or Files.  Using a form and a method (that calls
manage_editProperties(REQUEST)) I can set all the properties of my own
ZClass subobjects.  But I'm unable to set the Title property of a File
object.  Is there a secret trick?

-Magnus