How to output a menu showing 3+ levels of a page hierarchy branch?

My wordpress blog contains the following Page hierarchy:

-  page 1
     L page 1.1
     L page 1.2
-  page 2
-  page 3

I display a menu on my page.php template so that i can show a parent’s child items, and a child’s upper parent level, like this:

if($post->post_parent){
    $page = get_page($post->post_parent);
    $categoryTitle = $page->post_title;
    $children = wp_list_pages("title_li=&child_of=".$post->post_parent."&echo=0");
}else{
    $children = wp_list_pages("title_li=&child_of=".$post->ID."&echo=0");
}

Now there was a need recently to add an additional sublevel of pages, thus turning the system into:

-  page 1
     L page 1.1
         L page 1.1.1
         L page 1.1.2
     L page 1.2
         L page 1.2.1
-  page 2
-  page 3 

Problem is: if i’m on a page x.x.1 i don’t see page x in the menu, only the x.x parent.

Anyone has an idea on how to get all parents and children of a page ?