Problem in translations timing in custom theme

Hi,
I’ve a problem with the timing of string translations in a custom theme.
I’ve defined the domain in this way:

add_action('after_setup_theme', 'tuo_tema_load_textdomain', 0);
function tuo_tema_load_textdomain() {
  load_theme_textdomain('my-textdomain', get_template_directory() . '/languages');
}

However now I have this warning:

Notice: The _load_textdomain_just_in_time function was called incorrectly. The translation loading for the text domain my-textdomain was triggered too early…

because in some modules I’ve defined constants like this:

define(
 'DLI_SPINOFF_STATUS',
 array(
  'In attività' => __( 'Cerca area tematica', 'my-textdomain' ), 
  'Cessata' => __( 'Cessata', 'my-textdomain' ),
 )
);

I need to translate these values. What’s the best way to have constants translated without triggering the warning?

Thank you very much.

Claudio