Gamepad precision with sliders

Hi.

I am currently working on a menu where I need to move sliders. I am trying to setup the pad controls, and am facing an issue : how do I set up the precision of the slider ? What I mean is that when I move the slider with the joystick, it moves by big steps (I think it's a percentage of the slider max value), and I need more precision. Where can I change this value ?