RBAC and JAAS using a custom LdapLoginModule

Issue

• We are using RBAC and JAAS using a custom LdapLoginModule. How can we get the LDAP groups to be used with RBAC ?
• We are getting JBAS014788: Unexpected attribute 'assign-groups' encountered and we are using JBoss EAP 6.2 and JBoss EWS 2.1 in Red Hat Enterprise Linux Server release 6.6.

ERROR [org.jboss.as.server] (Controller Boot Thread) JBAS015956: Caught exception during boot: org.jboss.as.controller.persistence.ConfigurationPersistenceException: JBAS014676: Failed to parse configuration
        at org.jboss.as.controller.persistence.XmlConfigurationPersister.load(XmlConfigurationPersister.java:141)
        at org.jboss.as.server.ServerService.boot(ServerService.java:324) [jboss-as-server-7.3.0.Final-redhat-14.jar:7.3.0.Final-redhat-14]
        at org.jboss.as.controller.AbstractControllerService$1.run(AbstractControllerService.java:253)
        at java.lang.Thread.run(Thread.java:745) [rt.jar:1.7.0_75]
Caused by: javax.xml.stream.XMLStreamException: ParseError at [row,col]:[61,25]
Message: JBAS014788: Unexpected attribute 'assign-groups' encountered
        at org.jboss.as.controller.parsing.ParseUtils.unexpectedAttribute(ParseUtils.java:105)
        at org.jboss.as.domain.management.parsing.ManagementXml.parseJaasAuthentication