How do I change application database from ASPNETDB.mdf to my own

I am using Visual Studio 2008 Express.
I did this simple test:
I created a new Web project with a simple page that has a Log In. There were no databases in App_Data.
I used the configuration tool to create a Role and User.
I refreshed the project folder and behold AspNetDB.mdf has appeared in the App_Data folder.
I have checked the Web.Config file and there is NO Connection string to this database.
So how do I move the Roles/Users application data storage away from AspNetDB.mdf to my own database ??!!




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