Don't confuse arquillian properties with system properties. These are two different things. `arquillian.xml` is used to configure its extensions only. If you want to use config property do it regular maven way (or simply by adding -D to your build).
Another problem which you are facing is that you execute against remote container, which means it's started upfront as a different JVM process. If you are running in-container tests it's looking up system properties available for this JBoss instance. Maybe you should tweak your server configuration and put system property there?