Sorting Page Reference - Text Tags in Frontend

[torf]

Hi,
I've got a Page Reference Field in my Backend, to choose multiple options from a list. Now my Frontend retrieves the data and some additonal graphics from those pages in the order it has been chosen in the backend.  

foreach($my_page_data->my_text_tag_field as $item) {
	echo "url({$item->graphic->url()}), ";
}

But as those graphics are layered in my frontend, I always need them in the order they are listed in my backend. 

$my_page_data->my_text_tag_field->sort()

Just gives me an error.
Does anybody know how to sort the data in frontend so that it matches the sorting order in the backend page list, not the sorting order in the page reference field?

Thanks a lot