Interesting btw: when I try to use the ASUS inf file to install the driver though "update driver" the server crashes. That doesnt happen with any of the other inf's
Try this. Worth a shot if it works. Open up Group Policy Editor. (gpedit.msc)
Navigate to User Configuration > Administrative Templates > System > Driver Installation > Code signing for device drivers
Change the setting to enabled.
Below that change "When Windows detects a driver file etc..." to ignore.
Now open command prompt and run gpupdate /force
Now go into device manager, locate your sound driver, right-click and choose "Update Driver Software". Navigate to your INF, and see if it will install it.