Hi,
The Add button in the hibernate configuration editor does not reverse engineer tables in from database. All it does is allow you to add existing mapping files to your configuration.
This is mentioned in section 5.3, figure 8.
To reverse engineer tables, you have to open up a connection in the DB browser, and use the “Create Hibernate Mapping” context menu option available when you right click on a table.
Details of this process are present in section 5.4.
Let us know if you require further clarification,
Best,
Brian.