True..the client can not call these methods - actually the container calls these methods. However, the provider can put code in these methods. On page 320 of the spec, it does state you can call getUserTransaction() method in ejbCreate and ejbRemove. If so, you have the Usertransaction object, which means you should be able to call the UserTransaction methods.
I believe it is an error in the specs. That is, if you have access to getUserTransaction(), you should be able to call the UserTransaction methods.