I got it working!
Thanks for your advice.
For anyone interested I place the code below into the tpl_product_info_display.php
<!--bof Reviews button and count-->
<?php
if ($flag_show_product_info_reviews == 1) {
// if more than 0 reviews, then show reviews button; otherwise, show the "write review" button
if ($reviews->fields['count'] > 0 ) { ?>
<?php
foreach ($reviewsArray as $reviews) {
?>
<div class="ReviewBy"><?php echo sprintf(TEXT_REVIEW_BY, zen_output_string_protected($reviews['customersName'])); ?><?php echo zen_image(DIR_WS_TEMPLATE_IMAGES . 'stars_' . $reviews['reviewsRating'] . '.gif'); ?></div><br>
<div class="productReviewsDefaultProductMainContent content"><?php echo zen_break_string(zen_output_string_protected(stripslashes($reviews['reviewsText'])), 60, '-<br />') . ((strlen($reviews['reviewsText']) >= 100) ? '...' : ''); ?></div><br>
<br class="clearBoth" />
<?php
}
?>
</div>
<br class="clearBoth" />
<div id="productReviewLink" class="buttonRow back"><?php echo '<a href="' . zen_href_link(FILENAME_PRODUCT_REVIEWS, zen_get_all_get_params()) . '">' . zen_image_button(BUTTON_IMAGE_REVIEWS, BUTTON_REVIEWS_ALT) . '</a>'; ?></div>
<?php } else { ?>
<div id="productReviewLink" class="buttonRow back" style="clear:both"><?php echo '<a href="' . zen_href_link(FILENAME_PRODUCT_REVIEWS_WRITE, zen_get_all_get_params(array())) . '">' . zen_image_button(BUTTON_IMAGE_WRITE_REVIEW, BUTTON_WRITE_REVIEW_ALT) . '</a>'; ?></div>
<br class="clearBoth" />
<?php
}
}
?>
<!--eof Reviews button and count -->