The CLI does not allow for attributes to be defined when adding a new security realm at the host=master/core-service=management level.

To replicate, enter the following command in the CLI:
/host=master/core-service=management/security-realm=MyDomainRealm:add()

Within the add() operation I need to define an <authentication> section, but the CLI will not allow it. The message is:
Operation 'add' does not expect any property.