is it good to add columns in aspnetdb tables?

I m developing MVC3 application with SQL Server. For security I am using form based authentication (I need to provide authentication and authorization in application).
Currently user are being managed in aspnet_users table by Membership api. I am not getting any other option but to add columns in aspnet_users table.
I need to add the following other columns in aspnet_users table:
CreatedBy User id which create User CreatedOn DateTime EditedBy User id EditedOn DateTime IP Address I am thinking to write own methods to add these records and not try to disturb aspnet stored procedres.
Any gideance or advice please ? I m sure developers will have such needs.
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