Add load-more button at the end of Listview

Hi! I have a Listview binded to a list of objects using a custom cell on a StackLayout and I would like to add a button at the end of the list to add/load more items to the list.

I have read this post
http://stackoverflow.com/questions/26618361/best-way-to-add-footer-view-in-xamarin-forms-list-view
but I don't get how to mix two different cell types and how to know when the button is clicked.

I'm using forms for a cross-platform (android + iOS) app