form validation wih html input FILE

Hi, I'd like your opinion on the best way to do a form validation when the form contains a file upload object (<input type="file">) When the form does not validate, I try to re-show all values entered by the user. But, as far as I know, browsers do not allow to set the default value (local file path) of a FILE component I can get and display the default value in a label or text input, but how could I upload that file then? Will I be limited to display a warning message indicating that the user will have to select his/her file again?? thank you vincent