[libxml++] bad style

[Akbar <li...@cw...>]

Hey, this is my code:
void Wall::on_button_apply() {
    char *server_name = getenv("HOME");
    Glib::ustring filepath = server_name;
    filepath += "/.wallpapoz/wallpapoz.xml";
    xmlpp::Document document;
    document.set_internal_subset("wallpaper", "", "");
    xmlpp::Element* nodeRoot = document.create_root_node("wallpaper");
    Gtk::TreeModel::Children children = m_refTreeModel->children();
    for(Gtk::TreeModel::Children::iterator iter=children.begin();
iter!=children.end(); iter++) {
        Gtk::TreeModel::Row row= *iter;
        Glib::ustring temp2 = row[m_Columns.m_col_wallp];
        xmlpp::Element* nodeChild = nodeRoot->add_child("file");
        nodeChild->set_child_text(temp2);
    }
    document.write_to_file(filepath);
}

And my xml file will be like this:
<?xml version="1.0"?>
<!DOCTYPE wallpaper>
<wallpaper><file>/home/knight/wallpaper/eowyn2.jpg
</file><file>/home/knight/wallpaper/eowyn2.jpg
</file><file>/home/knight/wallpaper/eowyn2.jpg
</file><file>/home/knight/wallpaper/eowyn2.jpg
</file><file>/home/knight/wallpaper/eowyn2.jpg
</file></wallpaper>


How can I make it like this:
<?xml version="1.0"?>
<!DOCTYPE wallpaper>
<wallpaper>
<file>/home/knight/wallpaper/eowyn2.jpg</file>
<file>/home/knight/wallpaper/eowyn2.jpg</file>
<file>/home/knight/wallpaper/eowyn2.jpg</file>
<file>/home/knight/wallpaper/eowyn2.jpg</file>
<file>/home/knight/wallpaper/eowyn2.jpg</file>
</wallpaper>

Thank you.