public function buttonPayPal($oMembership)
{
$oPayPal = new PayPal($this->config->values['module.setting']['sandbox.enable']);
$oPayPal->param('business', $this->config->values['module.setting']['paypal.email'])
->param('custom', $this->session->get('member_id'))
->param('amount', $oMembership->price)
->param('item_number', $oMembership->groupId)
->param('item_name', $this->registry->site_name . ' ' . $oMembership->name)
->param('no_note', 1)
->param('no_shipping', 1)
->param('currency_code', $this->config->values['module.setting']['currency'])
->param('tax_cart', $this->config->values['module.setting']['tax_vat.percentage'])
->param('return', Uri::get('payment', 'main', 'process', 'paypal'))
->param('rm', 1)) // Auto redirection in POST data
->param('notify_url', Uri::get('payment', 'main', 'notification', 'PayPal'))
->param('cancel_return', Uri::get('payment', 'main', 'pay', '?msg=' . t('The payment was aborted, no changes have been made to your account.'), false));
echo
'<form action="', $oPayPal->getUrl(), '" method="post">',
$oPayPal->generate(),
'<button type="submit" name="submit">', static::buyTxt($oMembership->name, 'PayPal'), '</button>
</form>';
unset($oPayPal, $oMembership);
}