Screen Exit me21n

Hi,

For Example If I have to enhance the screen in me21n at the header level to add another tab. then my assumption is I need to go to the se51 and then find the suitable screen basing on the screen number and then add the tab over there with some fields on it and create a Ztable basing on the fields and then find a suitable user exit or BADI and then update the customm fields which are created in se51.

Is my assumption correct or I have to proceed in some other way..please let me know the procedure.

Thanks in advance,

Sagar.