Use my own database to authenticate Pentaho

Hello ;
I'm working with Pentaho Server CE 6.1 and i want to authenticate using my own table from postgreSQL database.
I read about how to use PostgreSQL as a repository Database https://help.pentaho.com/Documentati...F0/0P0/030/010
But not what i want , i have users and password (hashed) stocked in my database and i want to use them to authenticate from Pentaho SERVER CE.

Thank you ;