Query post in dynamic sidebar

I’m using a dynamic sidebar. It works fine, except for the fact that I want it to show just one of my categories. Suggestions on how? This is how I tried, but it ain’t working:

<ul class="xoxo">
<?php query_posts('category_name=news'); ?>
<?php if ( ! dynamic_sidebar( 'primary-widget-area' ) ) : ?>
<?php endif; // end primary widget area ?>
<?php wp_reset_query(); ?>
</ul>