Jocker, there are plenty of sources on the internet to help. Check out:
4GuysFromRolla.com
msdn2.microsoft.com
In fact the page I found from Microsoft, the latter of the two links above, gives you the answer your looking for.
<roleManager enabled="true" />
"This configuration enables role management and causes your application to use the default provider named
AspNetSqlRoleProvider defined in the Machine.config file. This uses the local SQL Express instance.
To
use a role store in SQL Server, add a connection string to point to
your role database and add a role provider definition in the Web.config
file, as shown here."
<configuration>
<connectionStrings>
<add name="SqlRoleManagerConnection"
connectionString="Data Source=sqlinstance;
Initial Catalog=aspnetdb;Integrated Security=SSPI;">
</add>
</connectionStrings>
</configuration>
<roleManager enabled="true" defaultProvider="SqlRoleManager">
<providers>
<add name="SqlRoleManager"
type="System.Web.Security.SqlRoleProvider"
connectionStringName="SqlRoleManagerConnection"
applicationName="MyApplication" />
</providers>
</roleManager>
Hope this helps or you've all ready found the solution.