Get RoleId from created role

Hello,
I was planning to connect a table in my database to the aspnet_roles table. The best way to do this is by referencing the RoleId as a foreign key. However, I can't find how to get the RoleId of the newly created Role in my code. Is this scenario overlooked in the RoleProvider model? Because I can get the UserId of a user with the Membership provider, no problem.
Thanks! 
...