Sending emails from EC2

Hello,

I have an application running using EC2 (using Ubuntu 8.04) and S3. Would like to set-up a MTA (Postfix) on the EC2 server so it can deliver mail to the SMTP server running outside the AWS environment (Liquid Web).

Found this guide for Ubuntu and Postfix (https://help.ubuntu.com/8.04/serverguide/C/postfix.html). This is written with the context that the local server will act as a SMTP/POP3 server.

Could anyone help me set up Postfix for the purpose of delivering mail to another SMTP server?

Many thanks.