I have a client that has a single 2008 Server that is running HyperV. One of his servers is utilized as a Terminal Server. He is wanting to upgrade to 2008 R2 and RDS. My plan is to purchase a 2008 R2 Open Licenses along with RDS CALs. Just want to make sure that 2008 R2 can operate as a guest on a 2008 (Not R2) HyperV Server. Any one done this?