I'm trying to get <li class="menu-first"> and <li class="menu-last"> ...
<?php
show_menu2(1, SM2_ROOT, SM2_ALL, SM2_ALL, '[if (level=2){<li class="[class]">[menu_title]}else{<li class="[class]">[a][menu_title]</a>}]', "\n</li>", false, false, false, '<ul id="header_menu" class="menu">');
?>
<?php
show_menu2(1, SM2_ROOT, SM2_ALL, SM2_ALL, '<li class="[class]">[if (level=2){[menu_title]}else{[a][menu_title]</a>}]', "\n</li>", false, false, false, '<ul id="header_menu" class="menu">');
?>
that's all...