In Visual Web Developer 2010 I can't create the ASPNETDB.mdf file?

I have a 64 bit version of SQL SERVER EXPRESS R2 and Windows 7 64 bit. I get the Cannot find data source error if I push Security in the WSAT and the ASPNETDB.mdf is not created. I have tried using the ASPNET.reg tool and it does not help. Any suggestions would be helpful