RDP - Authentication

[JTM_TEXAS]

I have been trying to get RDP authentication running with a Mac OS 10.6, 10.7 or 10.8 host for almost a year now, and so far have had zero success.

The issue appears to be that VRDP requires the authentication to be sent with the connection request, while the MS RDC for Mac software doesn't send it until after the connection. I have used every RDP client software I can get my hands on, none of them work right.

NULL works just fine, but I am wanting to use Virtualbox in a professional environment and there could be some confidential information on the server that I don't want just anyone to be able to log into. External and Guest authentication both give the same message:

"YOU WERE DISCONNECTED FROM THE WINDOWS-BASED COMPUTER
Someone with access to the Windows-based computer may have ended the connection, or the Windows-based computer has dropped the connection.
Try reconnecting to the Windows-based computer, or contact your administrator."

This issue has been ongoing for quite a while, does anyone know of a work-around?