How Do I Implement the Callback Model in an Authenticated Environment?

Customers can encounter authentication issues when implementing the DocuSign Callback Model in password-protected environments such as Salesforce. In Salesforce, customers typically create a REST endpoint for the Callback URL attribute of the call.  In this case, there is another mechanism in Salesforce called a Remote Action call. This is a way to expose controller methods to JavaScript to bypass authentication issues. Customers can have the callback method call that JavaScript method instead of trying to post to a URL.  Customers can perform a find and replace on the string sent back from the Quik! web service to rewrite that method to call their JavaScript method instead of sending an Ajax callout.