Bootable Sarge customs CD

[Philippe WAUTERS <philippe.wauters@opencom.be>]

I want to create customized Sarge cd's to give away during classroom sessions. 
My first idea is the following :

- copy the content of the official "netinst" cd to a directory on my machine
- copy supplemental files there (for example extra packages in pool/main)
- make an image of the content of this directory with :
  mkisofs -r -b boot.img -c boot.catalog -o ../my-customs-cd.iso .
- burn that image with k3b

I have picked-up different files from official Debian mirrors to replace  
"boot.img" in my command above (either 1440 k or 2880k), but I had always one 
of the following problem :

- no boot at all
- a "boot failed" message
- boot ok with 1440k images but without the normal Sarge choices (linux26, 
expert ...) and request for a "root" floppy.

Does anybody know the right file to pick and where to find it?

Thanks

Phil