Not able to get Oracle stored procedure return value passed to Powerbuilder

I have an Oracle Stored Procedure that receives a string value and returns a string value..  When I call it from Powerbuilder, it executes but does not send the return value of a string back.  I am trying to encrypt a string in Powerbuilder, pass it to a .net web page and then decrypt so I can check the security tables for permissions to view the web page.  I have tried creating a simple stored procedure that takes a string and returns a string to Powerbuilder; but even that is not working.  Any suggesstions?

Oracle Procedure:

CREATE OR REPLACE
PROCEDURE               TESTINOUT_VARCHAR
( P_STRING IN VARCHAR2, P_OUT OUT VARCHAR2)
IS

   BEGIN  
      P_OUT := P_STRING || 'TESTING';

END TESTINOUT_VARCHAR;

Powerbuilder Call:

string p_string ='                                 '

Declare TestingString procedure for TESTINOUT_VARCHAR(:ls_group, :p_out) using SQLCA

Execute TestingString;

IF SQLCA.CODE = 0 THEN

FETCH TestingString into:p_out;

End If

p_string = p_out;