This is a huge feature and would greatly increase the data entry workflow if the uploaded file list is persisted across model validation errors on post back of the web form.  Having this capability will allow us to develop forms with the asyncupload control right on the data entry form.  As it is now, we have to separate the data entry workflow where 1) user has to create and save the data entry form to ensure no model validation is triggered.  2) once the form is saved user must open a separate read-only version of the form to attach files (you can't allow edit of existing data since model validation will be triggered again).  Having this feature dramatically improve the data entry workflow allowing textual data entry and selection of files to be uploaded and saved in 1 step.  Thanks for your consideration!