title: Paypal Express Checkout provide full items discount
body: <p>I'm using Express Checkout in Paypal and trying to pass discount as a separate item (according to manual this is supported).</p>
  
  <p>I pass the following part (full discount on the item, but require to pay shipping):</p>
  
  <pre><code>&amp;NOSHIPPING=0
  &amp;PAYMENTREQUEST_0_SHIPPINGAMT=2.00
  &amp;PAYMENTREQUEST_0_SHIPDISCAMT=0.00
  &amp;L_PAYMENTREQUEST_0_NAME0=Item1
  &amp;L_PAYMENTREQUEST_0_QTY0=1
  &amp;L_PAYMENTREQUEST_0_AMT0=25.90
  &amp;L_PAYMENTREQUEST_0_NAME1=Discount
  &amp;L_PAYMENTREQUEST_0_QTY1=1
  &amp;L_PAYMENTREQUEST_0_AMT1=-25.90
  &amp;PAYMENTREQUEST_0_ITEMAMT=0.00
  &amp;PAYMENTREQUEST_0_AMT=2.00
  </code></pre>
  
  <p>But I get <strong><em>"The totals of the cart item amounts do not match order amounts."</em></strong>
  I checked many cases and it seems that all other issues people had are already addressed in my example, but it still doesn't work.</p>
  
  <p>Any hints?
  Thanks!</p>