firstly u need to add new item to your server+client
then make your own npc to give u the new item..use this very simple query to get the expballpack..
Code:
delete from cq_action where id >= 978859 and id <= 978861;
insert into cq_action (id,id_next,id_nextfail,type,data,param) values
(978859, 978860, '0', 501, 724040, '10 10'),
(978860, 978861, '0', 502, [COLOR="Red"][B]ITEMID[/B][/COLOR], ''),
(978861, 000000, '0', 126, 000000, 'Enjoy~your~Multi~EXPBALLPACK!');
NOTE: change the
ITEMID to your new item id u make in client side
itemtype.dat