Solved: See the two lines I commented out in /lib/XPay/Skin/Payment/Main.php
PHP Code:
<div class="payment-warning">
<?php $this('Label_Text')->write('Do not use the BACK button in your browser to avoid placing the order twice.'); ?>
</div>
<h1><?php $this('Label_Text')->write('Credit card details'); ?></h1>
<!-- <?php $this('Label_Text')->write('Payment method'); ?>: --!>
<?php $this('Label_Text')->write($this->getPayment()->getPaymentConf()->get('name'), false); ?>
<?php $this('Form')->begin('main', 'pay', array('token' => $this->get('token'), 'action' => 'pay'), XPay_Transport_Request::POST, array('onsubmit' => 'javascript: return checkCCDataForm(this);')); ?>