I'm attempting to start a Workflow via an AWS Lambda function that uses nodejs to make an HTTP POST request to the Workflow Web Service. I can get it to work by enabling Anonymous Authentication in IIS for the Workflow virtual application, but that  won't be an acceptable solution. How would I pass domain credentials in the POST request to ensure it gets authenticated by our Workflow server?

Another issue I've had during testing is passing a variable in the POST request that contains an ID (unrelated to any Workflow related IDs). I don't see it anywhere in the tokens from my testing. I'm passing a JSON object in the request body like this:

{
  "WorkflowName":"TestWorkflow",
  "formId":"{id from another app}"
}

This is to pass to an SDK script to utilize in later processes.