Hi
I had the same problem and i solved it using language files. I declared the name of each extrafield and the value (if you use select boxes or radio button) in language files and when i want to display it translated i modified the template for k2 to representate the extra field translated using JText function.
EJ: If you need an extra field to say the kind of fruit you can declare the extra field like:
FRUIT: APPLE | LEMON
You can define this traslations in files
EN.ini
FRUIT = Fruit
APPLE = Apple
LEMON= Lemon
ES.ini
FRUIT = Fruta
APPLE= Manzana
LEMON = LimΓ³n
And you can modify the template of k2 to display this extrafield translated
ej: JText::_( ‘FRUIT’ );
I hope it will be useful
Thnks!
AJ