I'm not sure why you have written your own GenericFacesPortlet. The whole purpose of the Portlet Bridge is to enable you to not have to write one, while also not worrying about how JSF works in a portlet.
How big a file is being transferred? If the file size is small the progress will never show anything because by the time another ajax progress call is made the file is already complete.
Oh no i didn't wrote my own i use the one bundled with gatein.
the issue i am talking about is similar to that liferay one : http://www.liferay.com/community/forums/-/message_boards/view_message/13979987