How to connect the VMRCPlus to Virtual Server!?

I have set up a Virtual Server R2 Sp1 on a 2003 platform, and had a XP installed as the guest OS.

I can connect to the Virtual Server with the VMRC, which included in the Virtual Server. But I can’t connect the server with the VMRCPLus, even on the 2003 server.

Is it due to I don’t have any Active Directory on the network?

If not, what’s the problem?