This is a bug in the 1.7.3 release driver that affects WDM support only on Windows for the FireStudio Products.
This is only an issue if you want to play audio from Windows Media Player, YouTube, or use a DAW that supports mutli-channel WDM I/O such as Sonar, N-Track, etc. If you need more than just ASIO, then please uninstall the 1.7.3 release and revert back to 1.7.2, then your WDM Channels will re-appear.