My question is about textfield autocomplete. I have this code:

function my_module_menu(){
  $items['my_module/textfield_autocomplete'] = array(
    'page callback' => 'my_module_textfield_autocomplete',
    'file' => '.my_modulemy_module.inc',
    'type' => MENU_CALLBACK,
    'access arguments' => array('access example autocomplete'),
  );
  return $items;
}

In my_module.module:

$form['fieldset7-wrapper']['prop'][$i] = array(
          '#type' => 'textfield',
          '#title' => t('Nombre de propietario'),
          // The autocomplete path is provided in hook_menu in ajax_example.module.
          '#autocomplete_path' => 'my_module/textfield_autocomplete'
        );

In my_module.inc:

function inmoges_ofertas_propietario_autocomplete($string) {
  $matches = array();

  // Some fantasy DB table which holds clientes

  foreach ($return as $row) {
    $value = check_plain($row->name).' '.check_plain($row->surname1).' '.check_plain($row->surname2);
    //$value = $row->name.' '.$row->surname1.' '.$row->surname2;
    $matches[$value] = $value;
  }

  // return for JS
  drupal_json_output($matches);
}

This works perfect. But I want that json return callback {nid; name} instead of {name,name}, and also show the name in textfield, but I can save nid in my form.

If I change to this my function ajax

$matches[$row->nid] = $value;

The previous sentence returns {nid, name}, but if I choose one value of the list name, in the textfield is shown the nid value, not the name value.

Any suggestions?