Sure, you can add the defaultProtocol tag to arq.xml like this:

https://github.com/arquillian/arquillian-showcase/blob/master/multinode/src/test/resources/arquillian.xml#L6

And if needed, override the info returned by the container using the "protocol" element on the "container" element like this:

https://docs.jboss.org/author/display/ARQ/Container+configuration