How to add .first and .last class to this code (code inside)

Hello,
I am printing my primary links with this code to help make dropdown menu
<?php if (isset($secondary_links)) {            //Code credit Wolfgang <a href="http://drupal.org/project/multiflex37" title="http://drupal.org/project/multiflex37" rel="nofollow">http://drupal.org/project/multiflex37</a>            $msm = variable_get('menu_secondary_menu', 0);            print theme('menu_tree', $msm);          } ?>
And this in template.php
<?phpfunction phptemplate_menu_tree($pid = 1) {  $msm = variable_get('menu_secondary_menu', 0);  if ($tree = menu_tree($pid)) {    $ul = $msm == $pid ? '<ul>' : '<ul class="menu">';    return "\n$ul\n$tree\n</ul>\n";  }}function phptemplate_menu_item($mid, $children = '', $leaf = TRUE) {  $msm = variable_get('menu_secondary_menu', 0);  $menu = menu_get_menu();  if (in_array($mid, $menu['visible'][$msm]['children'])) {    return '<li>'. menu_item_link($mid) . $children ."</li>";  } else {    return '<li class="'. ($leaf ? 'leaf' : ($children ? 'expanded' : 'collapsed')) .'">'. menu_item_link($mid) . $children ."</li>\n";  }}?>
But it is printing simple menu code like
<ul><li class="active">Home</li><li>About</li><li>About you</li></ul>
Can anyone edit this code to make it print menu with first and last class (or only first) like this
<ul><li class="active first">Home</li><li>About</li><li class="active last">About you</li></ul>
Thanks