In order for this rule to work, you must leave your computer on with the Mail application open during your absence. Otherwise, please set up your out of office reply in Piratemail.
Go to Mail > Preferences.
Click on "Add Rule"
In the Description field, name your new rule.
Change the drop-down menu under "if any of the following conditions are met:" and change it to "Account". Select your ECU account in the drop-down box next to it if it doesn't do so automatically.
Change the drop-down menu under "Perform the following actions:" to "Reply to Message" and then click on the button "Reply message text..."
Insert your message into the "Reply Message" text box. Click "OK".