Actually I am referring to this recent post http://scn.sap.com/docs/DOC-56562#comment-507221
With the help of this, I am able to achieve the log off functionality. But as I mentioned, when I configure the service of application of main web dynpro component in SICF, using "FIELDS AUTHENTICATION", under alternative logon procedure, as shown in this referred document, it is asking me to login thrice or so.
Note that the service which I am configuring in SICF, is of web dynpro component having component usages..I think that is triggering login screen more than once if I use fields authentication.
Regards,
Harsh