If you refer to atelier/language/es_ES.po … yes, that is where we already found them and they are both correct:
#: swift-framework/core/sf-header.php:1089
#: swift-framework/core/sf-woocommerce.php:619
#: swift-framework/core/sf-woocommerce.php:703
#, fuzzy
msgid “Your cart is empty.”
msgstr “Ver su cesta de la compra”
#: swift-framework/core/sf-header.php:1215
#, fuzzy
msgid “Your wishlist is empty.”
msgstr “Su lista está vacía.”
However, the english strings (see screenshots) still keep appearing. Regarding wordpress and theme translation we understand that it should be enough to switch the wordpress language itself (we did so to spanish) like described here: http://swiftideas.com/documentation/2014/05/26/translation/
Or is there anything else (beside just wordpress itself), something within the theme that needs to be switched in order to really make use of this “es_ES.po” file? Also we searched the whole database for these two strings without any success. So we still wonder where we need to change these two strings. Maybe does the use of a child-theme can cause such strange behaviours to language files?