Worldpay plugin not opening outside iframe

I have opencart working within iframes on my website, all is working fine but I've recently changed my merchant account to Worldpay from Payment Sense.

I've bought and installed the plugin for Worldpay, it works however...

The Payment Sense and Paypal plugins load their secure payment details form outside the iframe as I want it to but the Worldpay plugin keeps this page inside the iframe. (It works but it appears to customers as though it is not secure, which is why I want it to open seperatley from it).

Is there any way I can modify the code so that the payment page breaks from the iframe and loads into a new window like the the others do.

Thanks,
James