Subscribe to WSO2 ESB for REST URL

We successfully use the WSO2 ESB for basic mediation using REST for the caller and the service (via the message queue).

Now we are trying to use the themes and subscription model. However, unlike other parts of the ESB where you can change the message format for POX, there is a way in the subscription interface to define the payload format for the URL. The ESB always sends soap to the URL, although we want it to send POX. We do not want to write SOAP services.

Is there a way to change the format that the subscriber receives? I know that we can configure a proxy server, which then sends a message, etc., but it is cumbersome and cannot be automated for new services.