Well, actually I can confirm that it doesn't work. It seems as if the datasource is always bound beneath java:/.
How do you access the java:comp/ namespace? I see it listed in the JNDIView xml output but the datasource is always bound to a sibling context.
You get the java:comp/ namespace automagically when you create a reference to the DataSource inside the deployment descriptor of the EJB or WAR you are accessing the DataSource from.