These tests are built with ant. They are ran by deploying them as a war to a single JBoss instance which deploys the services needed by the test. This war also exposes a web interface that on request runs the tests and relays the results in the http response.
This process is automated by using ant to deploy the war and then making the http request and validating the response. See here in code for scripts: "XTS/localjunit/run-interop-tests.xml"
By using Arquillian we should be able to remove the ant script servlet, and web page then have Arquillian deploy the services and run the tests directly in the container.