Hi,
I assume that you have to configure "DiskFileItemFactory" and set a repository (location to store files) and a threshold (see http://commons.apache.org/fileupload/apidocs/org/apache/commons/fileupload/disk/DiskFileItemFactory.html#setRepository(java.io.File) .If both are not set, it discards files in the request I assume.
Hope this helps
Wolfgang