how to enforce "SSOONLYYMODE" to false while starting OAM ?

OAM version :- 12.2

we have two EBS  to enable SSO

first  with version:- 12.1

second with version:- 12.2

tried following "OAM 11g Does Not Send Authorization Responses To Downstream Application (Doc ID 1376402.1)" but not useful.

After setting value in oam-config.xml and start OAM services but when i recheck the file contain changes are not reflecting.

error :

oracle.apps.fnd.ext.sso.FndSsoException: FND-9930

         at oracle.apps.fnd.ext.sso.FndSsoLogin.doPost(Unknown Source)

         at oracle.apps.fnd.ext.sso.FndSsoLogin.doGet(Unknown Source)

         at javax.servlet.http.HttpServlet.service(HttpServlet.java:707)

         at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)