Right now, JBoss specific private attachments are passed in the EJB protocol message under different keys and aren't clubbed together under a single key. A better thing to do would be to club all these private attachments under a single key whose value will be a map of the individual attachments. This way all the private attachments will be available under a pre-defined key to the remote server side.

More on this available in this discussion https://github.com/jbossas/jboss-as/pull/2528#discussion_r1030768