Authentiacting eMail (courier) installation against a freeradius database

Hello, Authentiacting eMail (courier) installation against a freeradius database I have a mail installation using courier+postfix authenticating against a mysql database. I also have a freeradius installation. Both are working fine independently. Question:  How can I configure my mail installation so that it authenticates AGAINST the freeradius database and NOT the mysql database? Kind Regards, Kajani