Hi Eswar,
I do agree with what Ragav has mentioned,please follow the points mentioned by him.
To make sure that ur method is populating ur new parameter correctly with expected value in the run time, u can execute the BO method stand alone from SWO1,there u give the same input value(s) as it is passing in run time and make sure that the correct values is being populated to ur new parameter.
Make sure that the status of the BO is either in 'Implemented' or in 'Released' after generating the BO from WSO1 after ur code changes in method and in SWDD basic data ,starting event ,u can just deactivate the BO Event to WF binding once and then again activate ,generate binding do SWU_OBUF and test.
Thanks
Hafizul