Modification on the installer: "Debian software selection"

["Njes Nilsen" <are@spitfusion.no>]

Am a bit unsure whether this is the correct mailing list, but I ask anyway:

Under the installation of Debian Sarge you get the option to select  
packages to install.
There you are given these options:

[ ] Desktop environment
[ ] Web server
[ ] Print server
[ ] DNS server
[ ] File server
[ ] Mail server
[ ] SQL database
[ ] manual  package selection

What I want is to edit the installation so the user get another option  
here, which will install some given packages.
I've read some of the information about how to hack the installer on the  
debian wiki page, but can't find any information about how to do this.

Anyone got some documentation I can read / show me an example?

-Thank you