Hi Ankit,
I have used the same tutorial to create the Custom Tab in XD01.
But then I could only display the custom tab with the fields but could not save the fields to the table in KNA1.
I have even created a function module to to map the custom tab with the required fields.
I m doubtful about how to use the function module in the BADI Implementation namely CUSTOMER_ADD_DATA_CS.
Thanks & Regards
Harish