how to change the number of visible items in Elastislide vertical carousel

i'm using Elastislide vertical carousel from here

http://tympanus.net/codrops/2012/10/29/elastislide-revised/

and this is the vertical one

http://tympanus.net/Development/Elastislide/index2.html

I've changed the height of the carousel and the height of the < li > items inside it to display 4 items not 3 but after clicking any of the navigation arrows it keeps moving only 3 items not 4 and changed the dafault options of the js code from 3 to 4

$.Elastislide.defaults = {
    // orientation 'horizontal' || 'vertical'
    orientation : 'vertical',
    // sliding speed
    speed : 500,
    // sliding easing
    easing : 'ease-in-out',
    // the minimum number of items to show. 
    // when we resize the window, this will make sure minItems are always shown 
    // (unless of course minItems is higher than the total number of elements)
    minItems : 4,
    // index of the current item (left most item of the carousel)
    start : 0,
    // click item callback
    onClick : function( el, position, evt ) { return false; },
    onReady : function() { return false; },
    onBeforeSlide : function() { return false; },
    onAfterSlide : function() { return false; }
};

you can change it from here :

minItems : 6, //or any vlue you want to show