Upgrade to VS2010

[Statler6]

I'm trying to upgrade 200+ VS2008 solutions to VS2010. I've created a VBP project, which has a "Make VS 2010" action for each solution with Build behavior set to Upgrade.
But all I get is:
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Upgrading
Command: "C:\Program Files\Microsoft Visual Studio 9.0\Common7\IDE\devenv.com" Q:\Build\450\Components\SDLIB\SRC\SdTransfer\SdTra nsfer.sln /upgrade
"C:\Program Files\Microsoft Visual Studio 9.0\Common7\IDE\devenv.com" Q:\Build\450\Components\SDLIB\SRC\SdTransfer\SdTra nsfer.sln /upgrade
Microsoft (R) Visual Studio Version 9.0.30729.1.
Copyright (C) Microsoft Corp. All rights reserved.
Information:
This project/solution does not require conversion.
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How can I get VBP to use VS2010 instead of VS2008 for this action?