Exclude_tree still doesn't work

Hi guys,

i’m gettin crazy while trying to exclude some pages and its children to the menu of my website. Pages id are 40 and 61, so I tried to use this syntax:

<ul>
        <li><a href="<?php bloginfo('url'); ?>">Home</a></li>
        <?php wp_list_pages(array('title_li' => '', 'exclude_tree' => '40,61')); ?>
</ul>

result: only id 40 and its descendants are excluded. Converse result if commuting the ids.
Then i tried this

<ul>
        <li><a href="<?php bloginfo('url'); ?>">Home</a></li>
        <?php wp_list_pages('title_li=&exclude_tree=40,61); ?>
</ul>

but nothing change. So, any help will be much appreciated.