Host/Domainname change in: The Perfect Server-Debian Lenny (Debian 5.0) [ISPConfig 2]

I've just done "The Perfect Server - Debian Lenny (Debian 5.0) [ISPConfig 2]", and the server is now located in the DC

I made a misstake with the hostname / domain name, and now I want to change this remotely.
Example old: server1.example.com new: new.name.com
(problem is that I now have 2 servers with same hostname & domain name)

This is what I'm sure that I need to do (all done over SSH):
1)
edit /etc/hosts and change the
server1.example.com to new.name.com

2) do a
echo new.name.com > /etc/hostname
/etc/init.d/hostname.sh start
and verify if both are set the same with:
hostname
hostname -f

Now I'm stuck.
In the howto on page 4 step 12
How do I change the System mail name from server1.example.com to new.name.com, and how do I configure Postfix for the new TLS.
Do I just edit the needed data in: /etc/postfix/main.cf, delete the SSL certificates and re-create the SSL certificates?

Also.. Am I missing any other needed files that I need to change?
The setup is only a clean install of Lennt done the "The Perfect Server - Debian Lenny (Debian 5.0) [ISPConfig 2]" way.

The system is not running ISPconfig at the moment, so I'm okay on this.

 

Yes, that's right.

You might as well have to change the hostnames in the mysql.user table.

 

I'll get back on this.
Maybe I will do a re-install (I need to go to the DC anyway)