It’s also for PC, see here: click.
I think you can just download both files there, go to where you installed Cubase, open the VSTplugins folder (there is probably another VST plugins folder inside the first, open both.) Now create a folder called USM and put both files in there. Restart Cubase and you should be able to select it as instrument track output.
I’ll have a look on my own system when I get the chance concerning the automatic selection of the output VST, will get back to you on that.
@Lotney: You don’t need VST system link, doesn’t hurt but that’s for linking multiple PC’s together and streaming audio between them. You should also download and install asio4all and use that instead of the DirextX driver. Will not solve your problem but it’ll save you trouble later 