SQL Server db_owner

in my SQL2008 I have a user which is in the "db_datareader", "db_datawriter" and "db_ddladmin" DB roles, however when he tries to modify a table with SSMS he receives a message saying:

You are not logged in as the database owner or system administrator. You might not be able to save changes to tables that you do not own.

Of course, I would like to avoid such message, but until now I did find the way... Therefore, I try to modify the user by adding him to the "db_owner" role, and of course I do not have the message above.

My question is:

• Is it possible to keep the user in the "db_owner" role, but deny some actions like alter user or ? I try "alter any user" securable on DB level, but it does not work...

THANKS!

If the user is part of db_ddladmin it shouldn't be a problem. This is just a warning