Here's the code I used to make it work with a full cart of items.
Function called:
function render_paypal_checkout(ShoppingCart $shopping_cart)
{
return "
".render_shopping_cart($shopping_cart)."
";
}
Page source of cart before submitting to paypal
>
</pre>
<table>
Product ID
Quantity
Amount
PASTA
4
$15.96
CUMIN
2
$31.98
TOMATOSOUP
1
$1.33
shipping:
$31.93
total:
$81.2
</table>
<br><br><br><br><br><img alt="Paypal Checkout" border="0" src="https://www.sandbox.paypal.com/en_US/i/scr/pixel.gif" width="1" height="1"