PHP Worldpay Form Integration - prevent asking for customer details again

I'm currently looking to integrate Worldpay into a custom shopping cart. (What a horrible system to integrate with.) Anyway, from the little information I can find i've opted for a simple form for sending the payment information over.

But worldpay seems to want to ask for my customers cardholders details again on the worldpay form. Can these at least be prefilled?

My code is (for example):

<form action="https://secure.worldpay.com/wcc/purchase" method="POST">
  <input type="hidden" name="testMode" value="100" />
  <input type="hidden" name="instId" value="XXX">
  <input type="hidden" name="amount" value="20.00">
  <input type="hidden" name="currency" value="GBP">
  <input type="submit" value="Buy" />
</form>

I've dug around the WP documentation to no avail. Wish we'd opted for PayPal now!

You need to send the name and address details as well. See integration examples here, example 05 has name and address fields > http://support.worldpay.com/support/bg/index.php?page=development&sub=integration&subsub=examples#basic

and look at this pdf, around page 21 http://support.worldpay.com/support/kb/bg/pdf/rhtml.pdf