localTestingOnly option doesn't work when using the SAML2STSLoginModule

Issue

I am trying to use the localTestingOnly option in my SAML2STSLoginModule so I don't have to invoke an STS for validation, but this option isn't working.

My configuration:

<security-domain name="picketlink-sts" cache-type="default">
  <authentication>
    <login-module code="org.picketlink.identity.federation.bindings.jboss.auth.SAML2STSLoginModule" flag="required" module="org.picketlink">
      <module-option name="configFile" value="/example-sts-client.properties"/>
      <module-option name="localValidation" value="true"/>
      <module-option name="testingOnly" value="true"/>
    </login-module>
  </authentication>
</security-domain>

I get this error:

PL00102: Processing Exception:Authentication failed, principal=admin

I also see this message:

PL00105: When using local validation 'localValidationSecurityDomain' must be specified.