Searched and did not come up with a previous topic on Plus! (or DME). Has anybody come across switches for Plus! and Plus! DME (XP)?

I'm guessing it uses the Windows Installer, so these should work:

http://unattended.msfn.org/xp/applications/wininstall.htm

If it uses some other installer click Unattended XP CD on the page above, go to applications, and scroll down to the installer you need.