[jQuery] Ajax Upload

[Dave Maharaj :: WidePixels.com]

I an using the Valums ajax upload script, working fine...
 
But i have a question about using jquery to change the file name.
 
A user might be uploading 7.jpg and on the server I rename the file to match
the user and unique id so 7.jpg turns into something like
[username]_15987456.jpg
 
When the file is uploaded it says 7.jpg uploaded but how can i either rename
the file before uploading it and not renameit on the server or get the
[username]_15987456.jpg after the upload?
 
Thanks,
 
Dave