Hi @schanklies
The content type x-www-form-urlencoded is a special one. I had similiar issues but was able to fix this by using the Form Encoded HTTP entity Creator in between.
As such, all the request headers are captures into one. First, I created a component to fill in all the required parameters.
Then encode it (which creates a binary object )
Convert the binary object back to string gives the full request body.
Use that column as body content in the POST request.
Other than that; authentication is none and the Request header is Content-Type: application/x-www-form-urlencoded like you mentioned. This gives me the authentication bearer that I pass as flow variable upstream to other REST nodes.
Hope this helps.