Ok, I find a solution. I can export manually the field group to php and load these in the function.php.
Than I set the textdomain:
function custom_acf_settings_textdomain($domain) {
return 'textdomain';
}
add_filter('acf/settings/l10n_textdomain', 'custom_acf_settings_textdomain');
And all labels be found by Poedit template import. Thats fine 🙂
Is there a way to generate the php field group export automatically, by edit and saving the fields in ACF admin?