HttpRetriever - send application/xml instead of application/x-www-form-urlencoded ?

Is there a way to send plain XML or JSON body in POST request in HttpRetriever? Even if I add new Content-type=application/xml header, I get "Bad request" answer from the server. Alternatively, if I do not convert my XML column to BLOB, it can't be used by HttpRetriever.

What to do?

String input and custom content types beside the given ones are currently not supported. I'll add this during the next update. Stay tuned.

Latest nightly build support String input + setting custom content type in dialog. Let me know if that helps.

I see the change in this node UI but somehow it doesn't affect final outcome - still getting Bad Request.
This picture shows how I defined new content type:

It very much might be a problem with something else but there is no log to see actual HTTP requests issued by this node.

Logging is available in DEBUG level.