Vista - Virtual server 2005 r2 sp1 hard blocked on Server 2008 R2

My hardware does not support Hyper-V. I've already disabled Program
Compatibility Assistant (PCA) using gpedit.msc as described in

http://msdn.microsoft.com/en-us/library/bb756937.aspx

But setup.exe for Virtual Server R2 SP1 is still blocked by PCA with the
following details. Is there a solution? Thanks!

Description:
Microsoft Virtual Server 2005 R2 SP1 is incompatible with this version of
Windows. For more information, contact Microsoft Corporation.

Problem signature:
Problem Event Name: ApphelpHardBlock
Problem Signature 01: {11111111-1111-1111-1111-111111111111}
Problem Signature 02: {20a95612-5753-44df-9ff2-a5bef940512d}
OS Version: 6.1.7600.2.0.0.274.10
Locale ID: 1033