Hi at all, i'm quite new to JBoss. I'm searching documentation to understand how JBoss handle a connection to a DBMS and what components are involved in that kind of transaction (i've alredy read the adminguide.pdf). I've to modify the transaction that a remote user can make to a back-end database. I'll like to add some field to every kind of transaction (without knowing the table structure of the DBMS and what field the transaction use) to implement a exactly-once behaviour. Thanks for suggestion. Andrea Consiglio.