Outlook email stopped working due to unrecognized CA.

Last week, my Outlook email stopped working. Every time I tried to refresh my email/calendar, I would get an error about an invalid certificate.

I talked with my IT department and they mentioned that they had updated the SSl certificate for our OWA server about the same time that my email stopped working. After talking further with them, I found out that the new certificate was signed by a new CA (certificate authority) that Verisign just recently rolled out and was even causing problems with our IT supported phones (Windows mobile based devices). Once they were able to get an update from ATT with the new CA listed, those phones started working.

At this point, I hoped that if I deleted my account and recreated it, that I could get the phone to accept the certificate, even though it couldn't verify it. Now, when my phone gets the certificate, it complains and asks me if I want to accept it (I say yes), but my login still fails (it works when I log in through the phones browser). My IT believes that the failed login is still related to the failed certificate.

Does anyone know how I can get an updated list of CAs so that my phone will recognize a proper Verisign-signed certificate?