(JAAS) No loginmodules configured for

Olá pessoal. Numa tentativa de implementar o JAAS recebo a seguinte exception:

[code]Ago 20, 2012 11:45:52 AM org.apache.catalina.realm.JAASRealm authenticate
SEVERE: Unexpected error
javax.security.auth.login.LoginException: No LoginModules configured for ModuloLoginJAAS
at javax.security.auth.login.LoginContext.init(Unknown Source)
at javax.security.auth.login.LoginContext.(Unknown Source)
at org.apache.catalina.realm.JAASRealm.authenticate(JAASRealm.java:394)
at org.apache.catalina.realm.JAASRealm.authenticate(JAASRealm.java:334)
at org.apache.catalina.authenticator.FormAuthenticator.authenticate(FormAuthenticator.java:295)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:450)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:927)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:999)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:565)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:307)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)

[/code]

Implementei exatamente igual a este tutorial:

Obrigado desde já!