Change first tab shown at product page

-- url of the page with the problem -- : www.indianmotos.es/pruebamotocasion/
-- HikaShop version -- : 4.0.1
-- Joomla version -- : 3.4.8
-- PHP version -- : 5.3.29

Hi!
My product pages are in tabular mode and I would like the first tab shown to be the "Especificaciones" tab (shows the custom fields of the product) and the second tab to be "Descripción". Is this possible?
This is how it looks now:

I've just change it modifying the code at show_tabular.php

Thanks anyway! hehe