How to return Status Code 500 from a MockResponse

I have a Mock Service, under that, are numerous Mock Responses

The API I am emulating with SoapUI returns a HTTP Status 500 if I give it an invalid account to look up.

So in SoapUI, I want to create a Mock Response that will return an HTTP Status 500, along with a message (the message from the actual host contains the detailed information about the invalid account).

I've found a few posts out here telling me how to do that, but they must be for Soap Pro, because they do not work in Soap open Source.

Any suggestions?  Thanks in advance for your time.