anchor.diff:       "http://127.0.0.1:8080/1.0/kb/paymentGateways/hosted/form/268983f2-5443-47e4-a967-b8962fc699c5
   ----
   
  -Kill Bill will lookup the plugin associated with the default payment method for that account, and in turn the plugin will build the fields expected by the gateway (some require a field called Sum instead of amount, etc.).
  +Kill Bill will lookup the plugin associated with the default payment method for that account, and in turn the plugin will build the fields expected by the gateway.
   
  +Notes:
  +
  +* You can specify another payment method (other than the default one) via the *kbPaymentMethodId* query parameter
   
   ==== Process gateway notifications
   
  -Gateway notifications (Recurly push notificatoins, PayPal or BitPay IPN, etc.) can be processed through this API:
  +Gateway notifications (Recurly push notifications, PayPal or BitPay IPN, etc.) can be processed through this API:
   
   [source,bash]
   ----
  
positive.code:      -H 'X-Killbill-ApiKey:bob' \
       -H 'X-Killbill-ApiSecret:lazar' \
       -H 'X-Killbill-CreatedBy: creator' \
       "http://127.0.0.1:8080/1.0/kb/paymentGateways/notifications/killbill-paypal-express?customKey=value
  ----
  
  The plugin will deserialize either the request body and/or the url query parameters to process the notification.
negative.code: 
  ==== Build form descriptor
  
  The *build form descriptor* call is used when you need to prepare a payment form. There are two main scenarii:
  
  * The payment form is hosted on your own website, but the gateway requires custom hidden fields and visible fields need special names. In that case, the plugin simply returns the list of fields with their expected name (e.g. *Sum* field for the order amount, hidden *merchantId* field, etc.)
  * The payment form is hosted on the gateway website. In that case, the plugin builds a unique URL to redirect the user to by either:
  ** submitting the order information (amount, etc.) to the gateway which returns the location of the hosted payment form
  ** constructing the special URL via query parameters
  
  Given an order of $10, here is how you can get the HTML fields to build the form:
  
  [source,bash]
  