First of all, you will need to log into your Webmail account
You will see the following screen, or similar:
Click the `Auto Responders` link located along the bottom of the screen:
You should see the following screen or similar:
Click the `Add Autoresponder` button:
Then simply follow the instructions to setup your `Away/ Vacation` autoresponder message.
NOTE: Your `Away/ Vacation` auto response message will reply to ALL incoming messages including spam. If too many responses are going out, this could also be considered spam to some ISP's which could result in your email addresses being blocked. Just make sure to use best practices when initializing your `Away/ Vacation` Message and you shouldn't have any problems.
Another consideration, could be to notify your clients ahead of time; sending an email letting them know that you will be away, or unavailable, and that you will addresses their messages upon your return.