If the user is authorized to use invoices instead of credit cards, the PaymentGroupDroplet is initialized with different parameters indicating which PaymentGroup types to create. The PaymentGroupDroplet is introduced on checkout/billing_invoice.jsp as follows:

<%--
    The PaymentGroupDroplet is used here to initialize an InvoiceRequest
    PaymentGroup, and an OrderPaymentInfo object to associate a PaymentGroup with
    the Order.
--%>
<dsp:droplet name="PaymentGroupDroplet">
  <dsp:param name="clear" param="init"/>
  <dsp:param name="paymentGroupTypes" value="invoiceRequest"/>
  <dsp:param name="initPaymentGroups" param="init"/>
  <dsp:param name="initOrderPayment" param="init"/>
  <dsp:oparam name="output">
 
loading table of contents...