Getting USAePay to report cardholder name

My customer complained that they weren't seeing the cardholder's name on Drupal Commerce orders cleared through USAePay.

Looking at the module code, we can see we're sending the name data:

    'BillingAddress' => array(
      'FirstName' => $billing_address['first_name'],
      'LastName' => $billing_address['last_name'],
      'Street' => $billing_address['thoroughfare'],
      'City' => $billing_address['locality'],
      'State' => $billing_address['administrative_area'],
      'Country' => $billing_address['country'],
      'Zip' => $billing_address['postal_code'],
    ),

However, by default, the Drupal Commerce billing pane is set to collect the name as one field (single line). So though the module is sending first name and last name, the values are null.
To fix this -
Visit admin/commerce/customer-profiles/types/billing/fields/commerce_customer_address and make sure the customer profile Billing Address is set to submit the name as First Name, Last Name - see attached.

This will allow USAePay to receive and report the cardholder name.

Many thanks to djdevin for figuring this out.