that works (besides the other synchronized case where ACKed already happened). I'm doing these changes: - Adding a method on the postOffice, as I didn't want to deal with PM on the ServerConnectionEndpoint neither to expose PM on PostOffice: boolean messageExists(long messageId) throws Exception; - On FailoverValveInterceptor, I'm adding a header to the JBossMessage when a failure occurs. - I will also set a flag on TransactionRequest (protected boolean retry) but I will need to change the wireFormat a little bit to couple with that. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4011661#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...