Application Express :: EBS Authentication - Invalid Login Credentials

Am trying to use the same username and password of ebs to my standalone(not integrated with EBS) application. Am using apex 4.2 and Oracle Database 11g Enterprise Edition

CREATE OR REPLACE FUNCTION ebs_authenticate (
p_username   IN VARCHAR2,
p_password   IN VARCHAR2
)
RETURN BOOLEAN
AS
BEGIN
RETURN (APPS.FND_WEB_SEC.validate_login (p_username, p_password) = 'Y');
END ebs_authenticate;In Before Header Process

Get Username Cookie :    
       
:P101_USERNAME := apex_authentication.get_login_username_cookie;Set Username Cookie Process :

begin
owa_util.mime_header('text/html', FALSE);
owa_cookie.send(
name=>'LOGIN_USERNAME_COOKIE',
value=>lower(:P101_USERNAME));
[code].........

If i give ebs username and pwd means, it is not logging in as it is showing invalid login credentials.