Well you mount the VHD, let's say the driveletter is X: 
	Run this from admin Comment Prompt to load the offline system registry 
 
reg load HKLM\sys X:\Windows\system32\config\system
	than use regedit.exe and check "Start" dword value, it should be 0
 
	HKEY_LOCAL_MACHINE\sys\ControlSet***\services\iusb3hub 
	HKEY_LOCAL_MACHINE\sys\ControlSet***\services\iusb3xhc
 
	and finally unload offline registry with:
 
reg unload HKLM\sys
	 
 
	or use WinNTSetup on the mounted VHD, check the native USB3 checkbox on Ready page.
 
	BTW: If you don't select a source in WinNTSetup, but an installation drive with existing Windows Installation, 
	all tweaks and setting will be applied to the offline system.