I already have a Windows 8 Enterprise VM running with the RemoteFX display adapter so the RD Virtualization Host is configured properly. But now I have the Windows Server 2012 Standard client VM whose display adapter reports as a "Unknown Device", the hardware ID's are reporting it as the RemoteFX display adapter but no driver for it. I also put in the Integration Services Disk Setup, and it did perform an update to the Hyper-V integration. All Windows Updates are installed on the Virtualization Host Server, as well as the Server 2012 client.
Does Windows Server 2012 Standard not support a vGPU?
The documenation here is incomplete about this subject: http://blogs.msdn.com/b/rds/archive/2012/11/26/remotefx-features-for-windows-8-and-windows-server-2012.aspx