[X4U] non bootable DVD

[Xavier Noria]

I want to boot my MacBook from the install DVD (Tiger 10.4) but none  
of the tricks documented here

   http://www.macfixit.com/article.php?story=20050311073316780

works. When I insert the disk it doesn't show up in the list of  
possible startup disks in System Preferences. The Finder mounts the  
disk just fine though.

Any ideas?

-- fxn