How to handle scroll events on Ext.Panels in Ext Touch (Sencha Touch) ?

Question

I have two Ext.Panels, one the scrollingContent, inside another, called wrapper. Wrapper is less large than scrollingContent, so the latter scrolls horizontaly inside his wrapper.

I would like to handle scroll events and the position of scrollingContent inside wrapper after each scroll.

I did not find any solution for this. Any help would be really really appreciated.

Thanks in advance

var scrollingContent = new Ext.Panel({
    id: 'p1',
    layout: 'hbox',
    width: 1200,
    height: 380,
    //cls: 'blue',
    items: itemList
});

var wrapper = new Ext.Panel({
    id: 'p2',
    scroll: 'horizontal',
    width: 800,
    height: 380,
    cls: 'gray',
    items: scrollingContent
});