Jeff,

You are correct, but maybe you could come up with a workaround:

Using the same script you currently have you may be able to do so. I would
do it like this:

Create a script that refreshes the session every five minutes (or whatever
value you'd like). Also set up a loop that counts the number of times the
script has refreshed the page. To maintain that count between postbacks that
value could be stored in a hidden field or a cookie. Then you can vary a
page-timeout based on how many times you allow the script to loop before
logout. You could also open up a secondary window for this script to run in
so that you don't interfere with the upload. Or you may want to look into
utilizing multi-threading for the uploads.

Regards,