My question has been answered by Brian Rinaldi over at Remote
Synthesis (
http://www.remotesynthesis.com/blog).
He wrote an article on how to deal with uploads via Model-Glue. He
was able to clarify his post for me and now I understand what you
have to do.
What it comes down to is that you have to submit the name of
the fileField in a hidden input field (for lack of a better way at
this time) and pass that through your methods rather than the value
of your fileField.