Error response with no payload

[adahang]

We have upgrade from an earlier version of the ApiStudio. For backwards compatibility we would like the ability to define error responses with no payload, so we can return the error message payload in a custom header. This is how we had it configured before we upgraded to ApiStudio.
We have tried a number of things in ApiStudio but currently there is no way to remove the payload from an error response, for example from a 404 response.