Software Deployment

We are getting ready to update our servers to Windows 2003 server SP2. We are pretty low on hard drive space on some of our servers. I looked through some MS deployment guides and one of them says if I do a network install of SP2 the working files will no be placed on thr local hardrive which will save space. I extracted the files from teh update using the /x command line uption but when I launch the install from a network share and monitor the local hard drive space it still uses about 300mb of disk space temporarly during the install. Does anyone know what I am missing?

Here is the exact verbage from the deployment guide:

Network Installation
The network installation method discussed in the Deployment Methods section of this document has the benefit of reducing the amount of working disk space that the package installer requires. When the content is placed in a network location, the package installer uses that location as its cached working space instead of using the hard disk on the local computer. This can be very helpful for environments where storage space on the local computer is limited.
During a network installation of a Windows service pack, the ServicePackFiles folder is not created on the local computer because the package installer expects the computer to have access to that network shared folder in the future.
The following registry key points to the network shared folder.
HKLM\Software\Microsoft\Windows\Currentversion\Setup\servicepacksourcepath
Setup API functions use this location to retrieve files needed for Windows File Protection or Optional Component Manager. For more information, see Windows Service Packs and Optional Installed Components.For links to network installation resources, see Windows Deployment Guides.

Thanks!

Dave