uc_userpoints_payment module string for translation

This code doesn't allow translations into other languages:
drupal_set_message('You do not have enough points to complete this purchase. You have ' . $curUserPoints . ' but you need ' . $pointsNeeded . '. Please select another payment method.', 'error');

This code works for me:
drupal_set_message(t('You do not have enough points to complete this purchase. You have @curuserpoints, but you need @pointsneeded. Please select another payment method.', array('@curuserpoints' => $curUserPoints, '@pointsneeded' => $pointsNeeded)), 'error');