Ok, it's working this time, I tested sending email to both my email accounts and email accounts that are external to these servers. Sorry about the delay on this, I thought that I had this working several times, but didn't realize that it wouldn't relay emails to external domains when sending anonymously (from a PHP script).
I finally just bypassed Exchange and am using the IIS Virtual SMTP service that is installed on my other server... this is a more simple way to handling these emails.