Dynamics GP 2010 - Remove Old Users Imported From Version 9.0

Hello,

I have several users within GP 2010 that are no longer valid.  We upgraded from GP 9.0 to GP 2010 and elected not to migrate the existing users (thus new users were created).  The old users remain inside GP and I would like to remove them if possible.

Going to Tools->Setup->System->User and deleting one of the old users results in an error message that reads "This user does not have a corresponding SQL login.  To create a SQL login, enter a password and choose save."  

Since the SQL login does not exist, I followed this Microsoft KB article http://support.microsoft.com/kb/919345.  The article says to run 'DROP USER <user>' against the DYNAMICS database and the company database.  When I execute the query, SQL throws an error that reads "The database principal owns a schema in the database, and cannot be dropped."  

Can I delete the schemas that are owned by the users that I want to delete and then execute the 'DROP USER <user>' query for each user that I want to delete?

Thank you