How to restore file_upload value on error?

[eluser]James Spibey[/eluser]
Hi,

I'm trying to figure out the best way to retain the value of a file upload field between postbacks of a form. The problem I have is that the field isn't 'required' and so if they post a form and it fails validation, it isn't clear that they need to upload the file again.

Has anyone come across this?

Cheers

James