Here is a link to the example webform that passes info to the API
Here is the small amount of documentation available for the API.
The way the parameters read 'line_items' is an array that passes 'item', 'name', 'quantity', 'cost', price', and 'taxable'. I spoke to one of the programmers and he is stating that it must be a hash and that's why it's not working. I have tried using an associative array formatted with the http_build_query, but it's just not working. Anyone out there want to take a look at it for me and provide some suggestions. I've provided my code below, minus my API key.
$ch = curl_init();
curl_setopt($ch, CURLOPT_POST, 1);
$customer_id = '901992';
//$date = date('Y/m/d');
$date = '2014-08-01';
$data = http_build_query(array('date' => $date,
'customer_id' => $customer_id,
'name'=>'1 Year Flash Antivirus Subscription',
curl_setopt($ch, CURLOPT_RETURNTRANSFER, false);
$server_output = curl_exec ($ch);