Index: signwriter.module
===================================================================
--- signwriter.module	(revision 5)
+++ signwriter.module	(working copy)
@@ -326,9 +326,7 @@
 
     // make original renderer accept the already rendered text
     $link['localized_options']['html'] = TRUE;  
-    $link['localized_options']['attributes'] = array(
-      'class' => 'swm-h' . $height,
-    );    
+    $link['localized_options']['attributes']['class'] = implode(' ', array($link['localized_options']['attributes']['class'], 'swm-h'.$height));       
   }
 
   // call original renderer