diff --git a/admin/webservice/forms.php b/admin/webservice/forms.php
index dab9a42f661..5185b9bf323 100644
--- a/admin/webservice/forms.php
+++ b/admin/webservice/forms.php
@@ -160,7 +160,7 @@ class external_service_functions_form extends moodleform {
             $functions[$functionid] = $function->name . ':' . $function->description;
         }
 
-        $mform->addElement('searchableselector', 'fid', get_string('name'),
+        $mform->addElement('searchableselector', 'fids', get_string('name'),
                 $functions, array('multiple'));
 
         $mform->addElement('hidden', 'id');
diff --git a/admin/webservice/service_functions.php b/admin/webservice/service_functions.php
index d4f7da8ac16..fc0e8869a24 100644
--- a/admin/webservice/service_functions.php
+++ b/admin/webservice/service_functions.php
@@ -67,7 +67,7 @@ switch ($action) {
             //add the function to the service then redirect to function list page
             if ($data = $mform->get_data()) {
                 ignore_user_abort(true); // no interruption here!
-                foreach ($data->fid as $fid) {
+                foreach ($data->fids as $fid) {
                     $function = $webservicemanager->get_external_function_by_id(
                             $fid, MUST_EXIST);
                     // make sure the function is not there yet