Front-end Oracle Forms 6i with back-end Postgresql

Hello,
I am Khayer from Bangladesh.
I am trying to build an application regarding=20
Front-end Oracle Forms 6i with Postgresql back-end.
But I cannot make List of Value from Form Builder..because
the table names or column names not showing.
Could you please help in any way.
my e-mail: mmkhayer@yahoo.com

Thank you very much.
Khayer.