Feeds XPath parser - setting the created date of a node
You can try to use the hook_feeds_presave in a custom module : 

function mymodule_feeds_presave(FeedsSource $source, $entity, $item, $entity_id) {
  $your_import_date = explode('/', $item['your_import_date']);
  $your_import_date_formated = $your_import_date[2] . '-' . $your_import_date[1] . '-' . $your_import_date[0] . ' 00:00:00';
  $item['your_import_date'] = strtotime($your_import_date_formated);
  $entity-&gt;created = $item['your_import_date'];
}