It seems that another jar is missing from distribution, the Pax Web Extender JSP, as the log message says:
WARN [RegisterWebAppVisitorWC] Jsp support is not enabled. Is org.ops4j.pax.web.jsp bundle installed?
Obviously not! So I downloaded the latest version (0.7.1) of Pax Web Extender JSP and successfully deployed it:
INFO [BundleStartStopDeployer] Started: org.ops4j.pax.web.pax-web-extender-war 
INFO [Activator] Pax Web started
INFO [BundleStartStopDeployer] Started: org.ops4j.pax.web.pax-web-jetty-bundle 
INFO [JettyServerImpl] Pax Web available at [0.0.0.0]:
INFO [HttpServiceFactoryImpl] Binding bundle: [jboss-osgi-webconsole ] to http service
INFO [BundleStartStopDeployer] Started: org.ops4j.pax.web.pax-web-jsp 
But it doesn't seems to work because I always get the same WARN message above... suggestions?