How to automatically click ok on "Authentication Required" popup

Lately, I've been doing some web scraping automation. For the most part, I'm using Selenium, but Selenium doesn't seem to be able to automatically click "OK" when an authentication window pops up.

This python code, works with Redhat's Dogtail to auto-magically click "OK" button on an "Authentication Required" popup:

from dogtail import tree
from dogtail.utils import run
from time import sleep
from os import environ, path, remove
import sys
environ['LANG']='en_US.UTF-8'

#print tree.root.dump()
firefox = tree.root.application('Firefox')

#print firefox.dump()
#print dir(firefox)
#print firefox.findChildren()
auth_required = firefox.childNamed("Authentication Required")
#auth_required = firefox.child(name="Authentication Required")
ok_button = auth_required.childNamed("OK")
ok_button.click()
print 'ok button clicked now'
#print dir(ok_button)

NOTE:

Doing gui-automation this way may be a "bad idea", but I'm only doing this automation to scrape an internal webpage, and it only has to work on a very specific configuration -- Ubuntu 10.04 with Firefox.