About: Jesus Altuve

Hi!

I found your question looking for an answer myself, so I decided to figure it out. You simply need to add this to your theme functions.php:

function translate_custom_field($rec) {
        $label = $rec['field']['label'];
        $rec['field']['label'] = _x($label, "s2member-front", "s2member");
        return $rec;
}
add_action("ws_plugin__s2member_during_custom_registration_fields_before_custom_fields", "translate_custom_field");
add_action("ws_plugin__s2member_during_profile_during_fields_during_custom_fields_before", "translate_custom_field");

Obviously, make sure you DO have the entry in your .po file. The above fix assumes you are using
getext po/mo files and that the file is properly named (s2member-xx_YY.mo) and is in the plugins root directory and NOT inside the s2member plugin directory.

xx_YY is the locale, as in es_ES or en_US