Assigning an object(FormFile) to a dynamic form.

[Reza Aliakbari]

Hi,
 
I use dynamic forms in my projects; but this time I want to upload
A file and when I use   <form-property name="myFile"
type="org.apache.struts.upload.FormFile" /> 
An error occurs that says that cannot assign String to FormFile.
How can I use dynamic form with this kind of objects?
 
Thanks, reza.