diff --git a/service.inc b/service.inc
index a76423b..c8c039e 100644
--- a/service.inc
+++ b/service.inc
@@ -53,7 +53,7 @@ class SarniaSolrService extends SearchApiSolrService {
    * The special fields "search_api_id" and "search_api_relevance" are also
    * included.
    */
-  protected function getFieldNames(SearchApiIndex $index, $reset = FALSE) {
+  public function getFieldNames(SearchApiIndex $index, $reset = FALSE) {
     $ret = array();
 
     // Initially, map property Solr field names to themselves.