Installed a Sapphire AMD FirePro V5900 GPU in a HyperVisor server with a Xeon E5504 and running Windows Server 2008 R2 Standard, so the HyperVisor is working and Hyper-V manager recognizes and attaches the RemoteFX 3D Video adapter to the guest VM correctly. All guest additions are enabled for the VM also.
However, the guest VM (a terminal server also running 2008 R2 Standard) does not recognize the RemoteFX driver, still using the default VGA driver and now showing two "unknown" devices. I've looked through many forum posts and Microsoft's technet library, but it seems every issue is related to compatibility (which we have) or having RemoteFX enabled in the HyperVisor (which we've done). What is going on here?