Initializtion seems to fail if no directories defined

Initializing gldapo in Config.groovy with no directory definitions like the following:

ldap {
schemas = [LdapPerson]
}

and trying to programmatically define a GldapoDirectory in a Grails Controller causes this Exception:

errors.GrailsExceptionResolver org.codehaus.groovy.runtime.typehandling.GroovyCastException: Cannot cast object 'gldapo.search.SearchControls@a6a98e' with class 'gldapo.search.SearchControls' to class 'javax.naming.directory.SearchControls'

when trying to perform a search using that directory.

Adding a dummy directory entry in the Config.groovy initialization seems to correct the problem.