Oracle Forms

I wrote a package with invokers right to set up secure application role. The package runs successfully in sqlplus. I’d like to run this package for the Forms application

I tried to run this package in POST-LOGON trigger. The process failed with error ORA-06565 “cannot execute set_role from within stored procedure.”

Then I heard that dbms_session.set_role cannot be called in a logon trigger. Is there any alternate way to run the packge in Forms application? In sqlplus, the package can be executed directly (not inside logon trigger). How can I do it in Forms? Or what is the correct way to set up secure application role in Forms?

I just start to learn the Forms and use secure application role. Any helps are great appreciated.

Xiaoyun