class My_Page_Walker extends Walker_Page {

function start_el(&$output, $page, $depth, $args, $current_page) {
		if ( $depth )
			$indent = str_repeat("\t", $depth);
		else
			$indent = '';

		extract($args, EXTR_SKIP);
		$css_class = array('page_item', 'page-item-'.$page->ID);
		if ( !empty($current_page) ) {
			$_current_page = get_page( $current_page );
			_get_post_ancestors($_current_page);
			if ( isset($_current_page->ancestors) && in_array($page->ID, (array) $_current_page->ancestors) )
				$css_class[] = 'current_page_ancestor';
			if ( $page->ID == $current_page )
				$css_class[] = 'current_page_item';
			elseif ( $_current_page && $page->ID == $_current_page->post_parent )
				$css_class[] = 'current_page_parent';
		} elseif ( $page->ID == get_option('page_for_posts') ) {
			$css_class[] = 'current_page_parent';
		}

		$css_class = implode( ' ', apply_filters( 'page_css_class', $css_class, $page, $depth, $args, $current_page ) );

		$output .= $indent . '<li class="' . $css_class . '"><a href="' . get_permalink($page->ID) . '">' . $link_before . apply_filters( 'the_title', $page->post_title, $page->ID ) . $link_after . '</a>';

		$portfolio_archive_link = get_post_meta($page->ID, 'portfolio archive', true);

		if($portfolio_archive_link != ''){ // put the portfolio archive behind this Page
		global $wp_query;

	if(isset($wp_query->query_vars['post_type'])&& $wp_query->query_vars['post_type']=='portfolio'){
	  if ( $wp_query->is_archive )
        $css_class = 'page_item current_page_item';
  } else {
    $css_class = 'page_item';
  }
		$output .=  '</li>'."\n".$indent .'<li class="' . $css_class . '"><a href="/portfolio">' . $link_before . 'Portfolio' . $link_after . '</a>';

		}


		if ( !empty($show_date) ) {
			if ( 'modified' == $show_date )
				$time = $page->post_modified;
			else
				$time = $page->post_date;

			$output .= " " . mysql2date($date_format, $time);
		}
	}

}