Add variables in settings.php

$conf['i18n_variables'] = array(
// Site name, slogan, mission, etc..
‘site_name’,
‘site_slogan’,
…
);

or if it is your module you can do like this:

/**
* Implementation of hook_init().
*/
function uc_cart_init() {
global $conf;
$conf['i18n_variables'][] = ‘uc_cart_breadcrumb_text’;
$conf['i18n_variables'][] = ‘uc_cart_help_text’;
$conf['i18n_variables'][] = ‘uc_cart_new_account_details’;
$conf['i18n_variables'][] = ‘uc_checkout_instructions’;
$conf['i18n_variables'][] = ‘uc_checkout_review_instructions’;
$conf['i18n_variables'][] = ‘uc_continue_shopping_text’;
$conf['i18n_variables'][] = ‘uc_minimum_subtotal_text’;
$conf['i18n_variables'][] = ‘uc_msg_continue_shopping’;
$conf['i18n_variables'][] = ‘uc_msg_order_existing_user’;
$conf['i18n_variables'][] = ‘uc_msg_order_logged_in’;
$conf['i18n_variables'][] = ‘uc_msg_order_new_user’;
$conf['i18n_variables'][] = ‘uc_msg_order_submit’;
}