Pagination not working for "Pages"

Hi,

I can’t get pagination working on Pages (only works on Posts). I copied the following code into the page.php template:

<?php wp_link_pages(array('before'=>'<div class="post-pages">'.__('Pages:','hueman'),'after'=>'</div>')); ?>

And have included the following code on the text editor for the pages I want pagination for:

<!--nextpage-->

Can someone help?

Thank you!

Luis