I have the four pack, i need the lowr abs?

i did a workout and got a four pack in for days but ive been doing leg lifts flutter kicks and anything else for lower abes and still cant get them, any ideas?I have the four pack, i need the lowr abs?
ok, here's what I do...
lay down and grab hold of something behind you so you can support yourself, then you do leg lifts and lower them down and keep doing that, also do some excersizes on the balance ball, doing the leg lifts holding onto a banister or something taller.
good luck, I hope it works for you.
Cardio workouts with step aerboics. Your constantly steping up and down while pushing your abdomin in. It works your core great.