[CentOS] kickstart installation from usb key

From: Georghy <fusco at wanagain.net>
> Now I'm trying a simple task
> i only want to install package wich are in the first cd-rom of CentOS 
> (not my custom.iso), the official iso but I just want the package in the 
> first CD
> after that I'll use a script which install the other packages I wanted 
> instead of doing it during installation

Use:
  %packages
  @base
But I don't know if base packages are all located on the first CD...
Why not put all the CD isos (or DVD)?
Is you usb key too small?

JD