If the only reason of installing VS2011Beta is to do actual development, I would strongly suggest that you reconsider. Using a Beta for real development is a recipe for real pain later. There is no guarantee that anything you create using a beta will be usable in any way with the release version.
As it happens, the Dev center
] does not mention Win7 in relation to metro UI apps - only Win8, so I would suspect it won't work.