Drivers in %Systemroot%\inf don't installed after Windows 8.1

[piglovesrat15]

Due to timing and testing constraints, MDT is NOT being used. I use WinPE 5x64 to boot up the machine and apply the Windows 8.1x64 wim image. The wim image doesn't have any additional drivers.

After Windows 8.1x64 wim image is applied, I copy the extracted drivers to %systemroot%\inf, restart the machine but the drivers don't get installed during the Windows 8.1 setup. This works perfectly in Windows 7x64.

Is there another location I have to put the drivers in Windows 8.1? Is there a better way to do so, beside injecting drivers to the offline wim image using DISM?

Thanks in advance.