I just tried downloading and installing the Orcas Beta 1 Virtual PC version. It unpacks two VHDs and a couple of VMC files. While there are instructions for how to load these in Virtual PC, they do not work for Virtual Server. It seems there is some trickery involved in getting this to work on Virtual Server 2005 that I might have spent hours looking for had it not been for a very useful post by Jason Nadrowski. In his post Setting up Visual Studio Code Name "Orcas" Beta 1 Team Suite (Virtual PC version) the pertinent part that I needed was this:
What isn't described in the instructions but perhaps should is how to link this base VHD to OrcasBeta1VSTS.vhd in Virtual Server. From the Virtual Server Left Nav, go to Virtual Disks group and then select Inspect. Select the Orcas VHD in the drop down and then click the Inspect button. This page allows you to modify the parent virtual hard disk(s) and therefore specify any path for the Base01.vhd.
Thanks Jason. Very helpful. What a wonderfully obscure setting to have to find.
One interesting thing that I noticed was that the path to the base VHD was called "TimeBombedBase". Hmm... :)