Customized page - how to deal with wrong logon

We have setup a customized portal (on a landing uri). It works fine until

 

the user enters wrong credentials: the user sees then the default Firepass

 

page (my.logon.php3) and it doesn't come back to this customized page.

 

How to :

 

- let the user redirected to the customized login page

 

- let the error message (for ex. authentication failed) be displayed on

 

the customized page as it does on a standard logon page.

 

Thanks!

 

Regards

 

Alexandre