Internationalization fails in shortcode inside a contact form

Hello! i’m developing a web, that uses your plugin to send mails. I’m inserting a shortcode (developed by me) inside the form of the contact form, and that shortcode uses internationalizacion functions ( __(), _e() ). They simply don’t work inside the form (the shortcode works, but no translation is run). If i put the shortcode ouside of the form it runs and the internationalizacion works fine.

Is there any “special action” i could do to make it work?

Thanks in advance!