As far as i can see you need to modify the setupldr.ex_
and also smss.exe in i386\system32 from the install dir.
Expand setupldr.ex_ and use PE Resource Explorer (which can edit exe files) to edit the files.
PE Resource Explorer can be found at
http://www.wilsonc.demon.co.uk/d6peresourceeditor.htm(or search for any resource hacker that can edit .exe)
I'm still in the progress of editting this, so i'm not 100% sure how it will behave after it has been editted (or if it's even the right files)

So if anyone tries this, feel free to keep me updated

Hope this is usefull