subtotal text in alv

Hi friends,

i my avl grid code, i want to use subtotal text . i tried in layout-subtotals_text ., then event subtotal_text . but it is not at all coming .. please if any one is having code or procedure ,please let me know..

how to get subtotal text, is it necessary that the field should be having enough space to display that. but i am just displaying 'HI' just for checking .. but it is not coming..

actually i want to display difference value = val1 - val2.

answer should come there .. is it possible ?

if text will come means where it will come , based on first columns it is finding subtotal, so in the first column ,actual value is coming..

thanks and regards,

kani.