Ubuntu Mailserver Running on Amazon EC2 Required

I am after someone to create and build a mailserver on my Amazon EC2 platform. I will supply you with the user credentials you require. Ideally, I'd like a web based panel to create additional users, but not essential as I can edit them directly in a mySQL db. To be built initially on a Ubuntu Micro instance with room to upgrade to a larger instance as and when needed. Please read the project first and write the word "Understood". Also write your steps and suggestions to complete the project with a short description of what you understood.