I hate to bump an old post but I found this extremely useful. I think I much prefer this to the native driver package model in terms of manageability - it's a lot cleaner to import and update driver packages. Thanks very much for the guide!
One thing though - I had issues with dism working until I removed the backslash off the driver path:
DISM.exe /Image:%osdisk%\ /Add-Driver /Driver:. /Recurse