ok if you are serving web pages with your server the previous solution doesn't work you migth consider to add virtual host on apache configuration files if you can see when you access
http://server/ is the web page you are serving the default one or some other you have. try access server-manager in this way:
http://server/server-manager as you can see it redirects automaticly to
https://server/server-manager thats what you need. So you can custom the template of the httpd service thats is under /etc/e-smith/templates/etc/httpd/conf/httpd.conf/VirtualHosts/27ManagerProxyPass
and add webmail to the list. Remember that custom template should go under /etc/e-smith/template-custom/.
Ok after customizing the template you must run next commands:
/sbin/e-smith/expand-template /etc/httpd/conf/httpd.conf
/etc/rc.d/init.d/httpd restart
this should work fine.
always check if the change you made has been reflected to the configuration file. /etc/httpd/conf/httpd.conf