Help with horizontal sliding

I am working with a downloaded component that moves separate panels horizontally with an ease. there are 4 panels and they are controlled by 4 buttons to make them move.
The code for the panels is:

onClipEvent (load) {
targetx = 46.0;
delay = 8;
}
onClipEvent (enterFrame) {
distx = targetx-_x;
_x += distx/delay;
}

The code for each button is:

on (release) {
menu.targetx = 46.0;
}

The value changes with each button to move the panels.

My question is the buttons are actually buttons and I want to make them into movie clips
but when I do that and apply the same code it does not work.

Can this only be done with “buttons”?

I am trying to create a portfolio section that slides from panel to panel by thumbnails and left and right arrows.

Any help would be appreciated.