Auth. using LdapLoginModule does not return HTTP 500 when the LDAP server not available

I am using the LdapLoginModule from PicketBox in JBoss AS 7.1.1 to enable authentication against our company's LDAP server. However, I always get a HTTP 401 back no matter what kind of problem caused the authentication failure. Tracing through the Picketbox and JBoss code, I found that the problem seems to be from the private method "proceedWithJaasLogin" in "JBossCachedAuthenticationManager". At the end of this method:

...
catch (LoginException e)

{ // Don't log anonymous user failures unless trace level logging is on if (principal != null && principal.getName() != null || trace) log.error("Login failure", e); authException = e; }

// Set the security association thread context info exception
SubjectActions.setContextInfo("org.jboss.security.exception", authException);

return authenticated;
}

So basically, whatever exception that was sent up from the login modules is simply store in the thread context. The methods then simply returns true or false to indicate whether an authentication is successful or not. Whatever exception is store in the thread context doesn't appear to be used to generate a more appropriate error code to the client.

Steps to reproduce:

Just set up a LdapLoginModule and verify that it can be used to authenticate some users for a web application. Then shut down the LDAP server and try again. The client of the web application will always get back HTTP 401.