There is only a requirement to implement javax.resource.Referenceable if the AdminObject implements ResourceAdapterAssociation (plus java.io.Serializable) - which most AdminObjects do (hence the reason we had the bug) in order to share configuration with the ResourceAdapter instance.
See spec 13.4.23 -- the javax.naming.Referenceable part isn't clearly described in that section; I'll make sure that it gets described in JCA 1.7 or in a maintainance release of 1.6.
Both scenarios should work now :)