Invoice approval workflow

I need an application that be minimized in the Windows tray and periodically search for new xml files in a configured directory. When found, it ask to user for the departament and initiates a approval workflow. The workflow if defined for any departament in a database. This whill send emails to users for approve, re-asign to another user? or reject the invoice. All operations must be stored in a history. When finish, notifications will be sent to participants for make the payment. There are more details...