Actually I found that the inability to access the webmail part not to be on the firewall side. I did some digging in the config files in /home/admispconfig/ispconfig/lib/config.inc.php and found this line:
$go_info["server"]["server_url"] = "https://18.104.22.168:81";
I changed that to be the domain used to access the web site and now I can access webmail from remote locations.
Now I still need to figure out how to send e-mails from outside the firewall and how to fix the dates on the webmail.
If you have any thoughts please post!