Make avatar link to Twitter profile

How exactly should I use the template function get_comment_author_twitter_url($comment_id) to make the avatar link to the Twitter profile?

My comments.php contains:

<h2>Comments</h2>
	<ol id="comments">
		<?php foreach ($comments as $comment) : ?>

		<li id="comment-<?php comment_ID(); ?>" class="<?php echo $altcomment; ?>">

			<div class="gravatar">
				<?php if (function_exists('get_avatar')) {
					echo get_avatar(get_comment_author_email(),'40');
				} ?>
			</div>

			<div class="the_comment">
				<p><?php comment_author_link(); ?><br />
				<span class="small-text"><?php comment_date('F d, Y'); ?></span></p>
				<?php comment_text(); ?>
			</div>

		</li>

		<?php
			if ($altcomment == 'alt') {
				$altcomment = '';
			} else {
				$altcomment = 'alt';
			}
		?>

		<?php endforeach; ?>
	</ol>

http://wordpress.org/extend/plugins/twitter-avatar-reloaded/