In my post above your reply. You don't add the driver to the PE - the PE cannot detect the USB3 hardware anyway.
Short version is: In the HII driver tool -
- Locate the standard USB driver for the computer.
- Assign the driver file for the USB3 driver to your standard driver
- When HII runs the DISM scan on your target PCs it will detect the standard USB and save the driver file to the C:\Windows\LDDriverStore on your target PC
- When the PC reboots after CTOS it will look for drivers for all of the devices it has
- Windows supplies a standard USB driver so that one will be in the stock OS build
- Since you fooled it into copying the USB3 driver over earlier it will be there when the system needs to load it.