title: Magento: don't send tax to paypal/don't show tax in paypal emails
body: <p>I'm using magento 1.7, and one of the payment options is Paypal (UK) express checkout.</p>
  
  <p>The problem is that I don't want paypal to send out emails with any tax breakdown on, is there a more straightforward way of solving this (at the Magento or Paypal end) rather than hacking the core module to pass sub+tax as sub and 0 as tax?</p>
  
  <p>I can see that a lot of the fields are mapped in Model/Api/Nvp.php, but can't immediately see where I'd modify these values.</p>