window.addEvent( 'load', function() {
    var i = 0;	
	var elems = $$('#imgScroll ul li');
	if( elems.length == 0 ) return;
    
    var s = new Fx.Scroll( $('imgScroll'), {
        duration: 500,
        wait: false,
        transition: Fx.Transitions.Sine.easeInOut
    }).toElement( elems[i] );
    $('imgScrollRetroceder').addEvent('click', function(e) {
        Event(e).stop();
        if( i>0 ) {
            i--;
            s.toElement( elems[i] );
        }
    });
    $('imgScrollAvancar').addEvent('click', function(e) {
        Event(e).stop();
        if( i<elems.length-3 ) {
            i++;
            s.toElement( elems[i] );
        }
    });
});