SSO using URL to call transactions under NWBC

Hi all,

I have a following problem -  I need to:

   1. call (SAPGUI) transactions under NWBC using URL from external  (system)

   2. not to be asked for password if I'm already logged in NWBC.

I easily manage to do the point 1.   (using the help.sap.com instriuctions),    but do not know how to achieve the point 2.

Please let me know if this is possible and what options are available to us to achieve it.    

Some useful info;  We on  EHP7 for SAP ERP 6.0  EhP 3 ;      NW 740;  NWBC  4.0 PL13 ;    sso parameters are already activated  (login/accept_sso2_ticket= 1, login/create_sso2_ticket=2).

Thank you in advance for your help,

Best Regards,

IORDAN BENEV