Mini Server Hostname and User account e-mail addresses

So, I'm trying to set up this Mini running 10.7 Server.

I don't know where i'm going wrong.

The computer's name is "Mini"

The Host Name is : mini.socialgraphics.com

Here's my problem.

When i create a new user account the e-mail address is automatically set up as user@mini.socialgraphics.com

In order to get to the webmail interface, i have to use mini.socialgraphics.com/webmail

I'm looking to fix this. What i'm looking for is user accounts created as: user@socialgraphics.com and a webmail address of: socialgraphics/webmail

What am i doing wrong?

I'll have a second question after this regarding setting up mail in general. When I try to add the mail account information to an external machine, my work machine. It does not auto-fill in the incoming Mail Server address, for receiving, and SMTP will not add at all....

So, it's all wrong.. I just want a simple file/mail server running 10.7 with the domain socialgraphics.com Do I need to wipe this and start all over?

Thanks!