The audio chip on the ASUS CSB motherboard does not have audio drivers. However, you can use the Realtek HD 2.73 audio drivers for Windows 8. For information about how to install these drivers on Windows Server 2012, see the following link:
http://blogs.msdn.com/b/matthew_van_eerde/archive/2011/09/14/how-to-install-unsigned-drivers.aspx