ALV Grid Display Format to be changed

Hi,

I have a requirement wherein i hav copied a SAP transaction pgm to a Y pgm. and i want the ALV GRid Display Format to be changed i.e the column arrangement.

I have changed the col_pos fields of the table fieldcatalog which is correct even befor the call FM.

But the order of the columns do not..change...

What cud be the reason.

Does anybody know?