How to configure Postfix as a relay server

I have a Redmine instance, where email configuration is working fine without "TLS" (encrypted). Requirement is to configure the email emission part with TLS enabled?

 I tried to change the default file of Redmine (/usr/share/redmine/config/configuration.yml) to add the TLS enabled, with our relay server and all. But still the out put is emails without TLS.

Later I analyzed that, in that box, postfix is running and is responsible for making the encryption. Then i configure postix as a relay server to our remote mail server. Following steps helps to solve the issue

postconf -e 'relayhost = smpt.remote_mailserver.com'
postconf -e 'smtp_sasl_auth_enable = yes'
postconf -e 'smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd'
postconf -e 'smtp_sasl_security_options ='
echo "smpt.remote_mailserver.com   username@remote_mailserver.com:password" > /etc/postfix/sasl_passwd
chown root:root /etc/postfix/sasl_passwd
chmod 600 /etc/postfix/sasl_passwd
postmap /etc/postfix/sasl_passwd
/etc/init.d/postfix restart

Once I complete the above step, i got TLS enabled mails.
 
If, you need to read a related blog - http://skynetclouds.com/blog/configure-postfix-relay-centos/