Repeating or looping onRollOver mouse state on button

Hello m8s. I have one scrolling panel and i wont to control this panel with 2 buttons.
Left and Right. I use onRollOver mouse state and my panel is not animated. I told him how to move with action script:

this.levo_btn.onRollOver=function() {
baner_mc._x-=25;
};

and for going right:

this.desno_btn.onRollOver=function() {
baner_mc._x+=25;
};

How to loop this onRollOver state with AS becouse i dont wont to roll out mouse from button and than back to same button to repeat onRollOver state ?

I also have question how to stop my panel on exact x cordinate ?

I try with

if (baner_mc._x >=733) {
baner_mc._x =733;
}

baner_mc is instance for scrolling panel

733 is x cordinate for left edge of mu scrolling panel so i wont to stop him on this number when i scroll him right.

right adge is on -384.9

Pleas help me. Thank You !

Vladimir

PS: sorry for my bad english