mod_python + vampire file upload not working

[jacob.miles]

I'm trying to implement a file upload using vampire on top of
mod_python, using vampire's publisher. My form has an input that looks
like:

<form action="/FileAdmin/uploadFile" method="post">
<input type="file" name="uploadFile"/>
<input type="submit"/>
</form>

and in ImageAdmin.py I define the uploadFile function:

def uploadFile (req, uploadFile=None):
# etc.

the problem is that when this function is called, uploadFile contains
the filename as a string, rather than a file object or the mod_python
Field object. The string provided is also just the last part of the
filename, i.e. doesn't include any path, so I can't even access the
temporary file as I'd like.

Does anyone know what's going on here? Is this a problem with vampire?
mod_python? me?

- Jake