Custom post type and navigation

Hello!
I use this code to show custom posts:
<?php $loop = new WP_Query(array('post_type' => 'products', 'posts_per_page' => 1, 'category_name'=>'beds')); ?>

posts_per_page => 1 is to show navigation, because I got 2 test posts.

And then classical
<?php next_posts_link('Previous') ?> <?php previous_posts_link('Next') ?> etc.

But I havn’t any navigation yet.
Where am I wrong?

http://wordpress.org/extend/plugins/custom-post-type-ui/