You can (almost!) instead do:

    BrooklynLauncher launcher = BrooklynLauncher.newInstance()
            .brooklynProperties(BrooklynUrlLookup.BROOKLYN_ROOT_URL, launcher.getServerDetails().getWebServerUrl())
            .start();

But unfortunately that currently just takes a string key. Worth overloading that to take a config key, rather than us modifying it immediately after creating it.

But can do that in master, rather than for 0.6.0