I am needing a email web server. It will need to have built in calander, with an instant messager program, much like gmail. I am needing it to send an email with a security certificate that can only be opened with a computer that has the matching certificate. I want a questionaire to be asked before anything is sent from the email. It will ask if it needs a cert. If it does NOT, it will be sent normal mail. If it needs a cert, it will be sent with one. Security of this server is a must. It will need to be able to send and receive emails with different domains at the end. Example... if a user sends an email to companyA it will have companyA domain name. The web interface must be changable. It will need a logo place and have a color choice that the administrator can change..