Thanks in advance if anyone can shed light on this.

I have queries that I post to a vendor that uses what seems to me to be an unusual setup...everything's a POST and authentication is contained within the JSON body of the request. No headers are required.

If I post a file using the HTTP Job step, and get a file back, it works just fine. I have tried many, many variations on sending using the HTTP Post or REST Client transformation steps, but I always get a 302 - Object Moved to (.aspx URL-encoded string of my request) response. I would rather use the transformation steps for a variety of reasons.