Crystal report db problem

Hello,
I have Crystal 9.0.
Also I have Oracle 9i.

(I didn't any normal newsgroup for crystal, so I ask here,
please help).

I want to give the sql expression field (i.e package with parameters)
a formula field.

I see that crystal let me give in the sql expression field
only fields that are in the select sql statement.

I want something like :
In sql expression field :

my_package({formula field 1} , {formula field 2});

How can I do that, somehow ?

Thanks :)