I need to create a new MySQL user with limited permission on an existing Amazon RDS instance. After encountering a couple error messages I was sort of able to do this using the official MySQL Administrator tool and the user now appears in the list. However, I'm unable to assign any schema privileges as all the users are greyed out. I'm logged in as the "master user" created when the instance was launched. Not sure where to go from here. I do have the RDS command line tools installed but wasn't able to track down anything there either.