modifying easing options

I am trying to modify the duration of the animation on an accordion. I
was able to use the following to modify the 'open' portion of the
animation, but the slide up is still default speed- how can i add
another option to slow the slide up?
$.ui.accordion.animations.easeslide = function(options) {
this.slide(options, {
duration: 1000
});
};
Thanks!