..
501,Red_Potion,Red Potion,0,50,,70,,,,,0xFFFFFFFF,7,2,,,,,,{ callfunc "CustomBox"; },{},{}
function script CustomBox {
setarray .BoxItems[0],501,502,503;
set .Random, getarraysize( .BoxItems );
getitem .BoxItems[ rand( .Random ) ], 1;
announce "["+strcharinfo(0)+"] has just obtained a ["+getitemname(.BoxItems[ .Random ])+"] from a Custom Box.",0;
end;
}
edit item list here
setarray .BoxItems[0],501,502,503;
Re-Edit : Fixed Announcement Problems