EDIT

/**

 * Creates and array of defaults for drupal select form elements.

 *

 * @param $vocabulary_uuid

 *   The UUID of the CDM Term Vocabulary

 * @param $term_label_callback

 *   An optional call back function which can be used to modify the term label

 * @param bool $empty_option

 *   An additional element do be placed at the beginning og the list. This element will be the default option.

 * @param array $include_filter

 *   An associative array consisting of a field name an regular expression. All term matching

 *   these filter are included. The value of the field is converted to a String by var_export()

 *   so a boolean 'true' can be matched by '/true/'

 * @param string $order_by

 *   One of the order by constants defined in this file

 * @return array

 *   the terms in an array (key: uuid => value: uuid) as defaults for a form element that allows multiple choices.

 */

function cdm_vocabulary_as_defaults($vocabulary_uuid, array $include_filter = null) {

  $options = cdm_vocabulary_as_option($vocabulary_uuid, null, null, $include_filter);

  $defaults = array();

  foreach ($options as $uuid => $value){

    $defaults[$uuid] = $uuid;

  }

  return $defaults;

}