You can configure both membership provider and role provider to use different database
http://msdn.microsoft.com/en-us/library/vstudio/6e9y4s5t(v=vs.100).aspx
But you need first to configure your own database to store providrs data. This can be done using aspnet_regsql.exe tool
http://msdn.microsoft.com/en-us/library/vstudio/ms229862(v=vs.100).aspx