Reporting back with good news. I found a better workaround. I simply used Microsoft's Application Verifier tool to intercept the GetVersion/ GetVersionEx API calls to trick the application into thinking my source machine was Windows Vista.
Instructions on how to run Easy Transfer on Server 2008
1. Copy C:\Windows\System32\migwiz folder from Vista installation to C:\Windows\System32
2. Download Application Verifier from Microsoft here: Download
3. Launch Application Verifier. If you are using 64-bit Windows, launch the x64 version.
4. Click on File > Add Application
5. Navigate to c:\windows\system32\migwiz. Add migwiz.exe
6. Expand compatibility.
7. Place a checkmark in the HighVersionLie box.
8. Right-click on HighVersionLie and choose Properties
9. Input following values :For Server 2008:
Major Version: 6
Build Number: 6001
Product type: 1 For Server 2008 R2:
Product Type: 1
Leave rest as 0.
10. Save and close the program.
Launch Easy Transfer (migwiz) the application should now load.
I have tested this on both Server 2008 and Server 2008 R2 (physical machines) and it works great.