do I change this:
$messageStack->add_session('header', REVIEWS_APPROVAL == '1' ? MESSAGE_REVIEW_SUBMITTED_APPROVAL : MESSAGE_REVIEW_SUBMITTED, 'success');

to this:
$messageStack->add_session('review_text', REVIEWS_APPROVAL == '1' ? MESSAGE_REVIEW_SUBMITTED_APPROVAL : MESSAGE_REVIEW_SUBMITTED, 'success');

is that what will make it output by this one:
<h1 id="reviewsWriteHeading"><?php echo $products_name . $products_model; ?></h1>
<?php if ($messageStack->size('review_text') > 0) echo $messageStack->output('review_text'); ?>

??