Unable to get a valid UserTransaction

[macmirror]

I want to get a UserTransaction (not in a session bean) doing
as follows:

InitialContext context = null;
Hashtable props = new Hashtable();
props.put(Context.INITIAL_CONTEXT_FACTORY, "org.jnp.interfaces.NamingContextFactory");
props.put(Context.URL_PKG_PREFIXES, "org.jboss.naming:org.jnp.interfaces");
props.put(Context.PROVIDER_URL,"jnp://localhost:1099");

try {
 context = new InitialContext(props);
} catch (NamingException e) {
 // throw exception
}

UserTransaction utx = (UserTransaction)context.lookup("UserTransaction");

After the lookup I get back in utx an ServerVMClientUserTransaction object, but with TransactionManager tm=null and the Collection listeners = empty ArrayList, if I check in the debugger. Any operation on the object result in errors and consequently the UserTransaction is useless...

What am I doing wrong? Why isn't the TransactionManager injected into the returned UserTransaction?

Any hints and help welcome! ;-)