You now need to update the machine's policy using
gpupdate /force from the command line. Then reboot the machine for the change to actually take effect and enable the RemoteFX USB redirection option in your Remote Desktop Connection client.
Once it's enabled, access the Local Resources tab, click More under Local devices and resources, and you'll see a new Other supports RemoteFX USB devices setting. You can use this setting to map through many types of USB hardware that you couldn't with vanilla RDP USB redirection.
