Upgrading from 10.5 to 10.6 via command line

Hi all:

Can anybody tell me what package(s) should be installed when upgrading a 10.5 server to 10.6? I don't need any of the language kits or printer drivers or X11, just the basic install option. I'd like to install the packages via command line, but there are a few that look relevant and I'm not sure which ones to install.

These look promising:

MacOSXServerInstall.mpkg
MacOSXServerInstall.pkg
OSInstall.mpkg
OSInstall.pkg
OSUpgrade.pkg

Thanks,

Brewster