[Plugin: Ultimate CMS] Get field value on get_terms list

I need to make a list of journal volumes with publication year headings, like this:

2010
Volume 22
Volume 21

2009
Volume 20
…

The volumes are a taxonomy and the publication year is a taxonomy custom field created with Ultimate CMS.
Is this possible and, if so, how? This is what I have so far.

<?php	$taxonomy = 'volumes';
	$queried_term = get_query_var($taxonomy);
	$terms = get_terms($taxonomy, 'orderby=custom_sort&order=DESC&hide_empty=0&slug='.$queried_term);

	if ($terms) {
	  echo '<ul class="indice" id="indice">';
	  foreach($terms as $term) {

	  	echo '<li><a href="'.get_term_link($term->slug, $taxonomy).'">Volume '.$term->name .'</a></li>';
	  }
	  echo '</ul>';
	}
	?>

Thank you.

https://www.ads-software.com/extend/plugins/ultimate-cms/