I think using 0A1FailureNotification script can trigger the errors for your partner as a seperate conversation i guess you might have implemented this logic, and the receiving document conversation script includes processunHandleddocument step and after this step invoke a custom service which contains the smtp logic and using built-in TN services, where you can trace TN bizdocs if you receive documents with duplicate conversationIds and here do a errorhandling sequence and alert an email to both parties.
yes some work will be around this type.
HTH.
#Integration-Server-and-ESB#webMethods#B2B-Integration