Log in to SmarterMail interface for your domain name (http://mail.yourdomain.com) using your full email address and password.
Step 1: Mouse over the 'Settings' tab and click 'My Auto Responder'
Step 2: Check the 'Enable auto responder' option
Step 3: Click the 'Auto Responder Message' tab
Step 4: Create a subject and body for your auto responder
Step 5: Click the 'Save' link near the top
To turn off the auto responder when it's no longer needed, uncheck the 'Enable auto responder' option under the 'Options' tab.