Language button name undefined

[beechyrb]

Button names not properly defined for Bluepay Redirect payment method in admin files.

Line 213 - 215 of admin/controller/payment/bluepay_redirect.php

$data['button_release'] = $this->language->get('button_release');
$data['button_rebate'] = $this->language->get('button_rebate');
$data['button_void'] = $this->language->get('button_void');

Change to:
$data['button_release'] = $this->language->get('btn_release');
$data['button_rebate'] = $this->language->get('btn_rebate');
$data['button_void'] = $this->language->get('btn_void');

OR
Line 56 - 58 of admin/language/english/payment/bluepay_redirect.php

$['btn_release'] = 'Release';
$['btn_rebate'] = 'Rebate / refund';
$_['btn_void'] = 'Void';

Change to:
$['button_release'] = 'Release';
$['button_rebate'] = 'Rebate / refund';
$_['button_void'] = 'Void';