I believe this is new to SIU as of 10.4.3.
You can now, when choosing the source for a Network Install, after clicking the ‘Customize’ button, select install options the way you would during a local CD install.
For the enterprise this is pretty nice – for example, at the newspaper where I work we have roughly 10 ‘remote’ offices connected to our core network by T1 lines. Removing the enormous number of unneeded printer drivers in the base install is quite useful in this scenario.
by 
Isn’t SIU just the same as it was when it was released with Server Admin
Tools 10.4 back when Tiger Server came out? I don’t see a "SIU 10.4.3"
anywhere.
IIRC it is new to 10.4 though. Lot’s of people seem to have missed this tip in
their own exploration.
—
Breaking my server to save yours.
Josh Wisenbaker
http://www.afp548.com
It says version 10.4 in the Finder but the about box lists it as 10.4.3
One thing about the custom install, once you netboot, the hard drives you can
install to show up as folders. I hear this is only because an icon isn’t copied
when its built, should perform normally. My custom install has been working
fine.