I have a stupid question wanna to ask, How I can trigger the OnAuth Event?

I've try to write some code on TIdNNTPServer.OnAuth but it seem never run.

I catch the command from outlook express to my sample server program, I got
the following command:
AUTHINFO USER XXXXX
then the process stop. and then I use telnet to test again and still no
response, is there any way I can trigger OnAuth Event?

and also I just want to know I put the code in correct place if I want to
check the user infomation to my Backend database.

Thanks for help and sorry for my poor english

Philip Au