data is not displaying under custom tab in me23n on Header screen ,

I use the screen 101, and write the code in PBO and also use the sub screen not normal and i debug it data is displaying in internal table but is not reflecting on ME23N SCREEN , what will be reason behind it ??

it urgent .

I get the data from CDHDR table and i want to display on screen under custom tab on header , also using the user exit .

kindly help me in this regard.