i personally would not try to modify webmail, however this is what i did to create an intranet on port 81.
you need to create/modify 2 templates:
1: /etc/e-smith/templates-custom/etc/rc.d/init.d/masq/allow81
{
$OUT = allow_tcp_in(81, 1);
}
2: /etc/e-smith/templates-custom/etc/httpd/conf/httpd.conf/intranet81
Listen 0.0.0.0:81
NameVirtualHost 0.0.0.0:81
<VirtualHost 0.0.0.0:81>
ServerName 10.0.1.2:81
DocumentRoot /home/e-smith/files/ibays/intranet/html
ScriptAlias /cgi-bin /home/e-smith/files/ibays/intranet/cgi-bin
Alias /files /home/e-smith/files/ibays/intranet/files
</VirtualHost>
you should be able to work out what you need to do from this.
regards,
brenton