java.security.auth.login.config System property is always overriden by HST container regardless of its existence in system

When using an external JAAS module, 'java.security.auth.login.config' can be set as Java system property in the command line (See an example with JOSSO in [1]).

However, HST container always overrides the system property configuration given in the command line by its default configuration, classpath:org/hippoecm/hst/security/impl/login.conf, resulting in a severe failure to disallow an external JAAS configuration.

[1] http://www.josso.org/confluence/display/JOSSO1/Tomcat+6.0