problems with theme('pager')

i am developping a patch for epublish module, and i want to page the publications in stead of listing a big list and i dont know how to include the theme('pager') function. the code will sounds odd for those who are not indulged in the epublish's module codes.
Thanks for ur help in advance

 $order = variable_get('epublish_edition_order', 'DESC');
	$publications = db_query("SELECT * FROM {epublish_publication}");
	$header = array(t('publication/editions'), array("data" => t("operations"), "colspan" => 2));
	while ($publication = db_fetch_object($publications)) {
		$rows[] = array(l('<b>' . t($publication->name) . '</b>', "epublish/$publication->pid", array(), NULL, NULL, FALSE, TRUE),
							l(t("edit publication"), "admin/epublish/edit/publication/$publication->pid"),
							l(t("add edition"), "admin/epublish/add/edition/$publication->pid")
			 );
		$sql  = "SELECT * FROM {epublish_edition} WHERE pid='%d' ORDER BY volume $order, number $order, pubdate $order, eid $order", $publication->pid);
    $countsql = "SELECT COUNT(*) FROM {epublish_edition} WHERE pid='%d'";
    
    $sql .= tablesort_sql($header);
    $result   = pager_query($sql, 5,0,$countsql);
       
    $previous_volume = -1;
		$editions = array();
		while ($edition = db_fetch_object($result)) {
			if ($edition->volume != $previous_volume) {
			if ($previous_volume != -1) {
			$rows[] = array(implode('<br />', $editions), array('data' => t('volume name: ') . l(theme('epublish_volume_reference', $publication->pid, $previous_volume), "admin/epublish/edit/volume/$publication->pid/$previous_volume"), 'colspan' => 2));
					$editions = array();	
		  }
		}
			$editions[] = '-' . theme('epublish_edition_reference', $edition) . ' (' . l(t('edit edition'), "admin/epublish/edit/edition/$edition->eid") . ')';
      $previous_volume = $edition->volume;
		}
		if ($editions) {
			$rows[] = array(implode('<br />', $editions), array('data' => t('volume name: ') . l(theme('epublish_volume_reference', $publication->pid, $previous_volume), "admin/epublish/edit/volume/$publication->pid/$previous_volume"), 'colspan' => 2));
		}
	}
	$output = theme("table", $header, $rows);
  $output.=theme('pager', "epublish/$pid/v$volume", 10, 0);
	return $output;