Importing this into your registry before installing the device might work. I haven't tested it though...
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Driver Signing]
"Policy"=hex:00
I was testing this on my system. That first tweak I gave you probably won't work. It didn't for me.
This one did:
[HKEY_CURRENT_USER\SOFTWARE\Microsoft\Driver Signing]
"Policy"=dword:00000000
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Setup]
"PrivateHash"=hex:b5,d8,e5,40,81,96,7f,61,8e,11,34,97,82,bb,7d,01
That second entry(PrivateHash) you might want to import from your own registry. Right click on my Computer, Select Properties, Go to the Hardware Tab, click Driver Signing, Check Ignore and Make this action the system default, Click ok, Click Ok. Reboot. Launch Regedit and export this key:
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Setup]. You only need the "PrivateHash" Value so delete the others.
If importing this right before you install the Virtual drive doesn't work, you might try importing it from cmdlines.txt. Still might not work. You neve know about these tweaks.