Start by visiting your email account using webmail.
go to www.yourdomainname.com.au/webmail/
Login with your email address and email password.
Mouseover your email address in the top Right Hand corner then select the auto-responders option.
Click the large blue "Add Autoresponder" button
Adjust the following settings:
Character Set: DO NOT CHANGE
Interval: Maybe 24 hours would be a good setting here
From : your email address or name
Subject: up to your discretion
Message: Keep it simple here, do not use HTML
Start and Stop : use "Custom" to set a specific date to begin and cease sending this message
Press [CREATE/MODIFY] to save.
Repeat for each email address you wish to have an autoresponder for.