/rw/rapid/execution Web Services 1.0

How can I use these API to stop all tasks?
I get back always:
“UNSUPPORTED_MEDIA(415)”

Thanks

I found the answer: change the MIME type to

Content-Type : application/x-www-form-urlencoded

The task will not stop, but at least I am able to make a good request.

PLEASE: update and improve the documentation about web service, it has a lot of errors, and it missing a lot of information!!!