It was necessary to update the SSL Certificate on our Exchange 2007 server so Webaccess email would work properly. I have always struggled with SSL Certificates. We ended up getting our SSL Certificate through GlobalSign. They have 2 pages on their support section that did a good job of detailing the steps for installing SSL certificates on Exchange 2007.
Here is an easy way of listing the mailbox sizes for everyone on your Exchange 2007 mail server.