Hi,
I couldn’t get any type other than “application/json” or “text/plain” to work with webhook. In addition there are no services to manipulate xml or soap in workflow, so you would have to use a flow service anyway.
Also I should have explained that it would be easier to build a SOAP API, that way you avoid the whole xml and translation bit, but I see that you posted that as a separate question.
So for anyone interested in this subject please refer here
regards,
John.