Logging data changes on Informix 7.22 ?

We are in the process of designing a new application which is based on an Informix database. The db will be accessed via Unify Vision, Borland Delphi and ODBC. We need to log all changes to the database. One solution i am thinking about is to use stored procedures and triggers to save before an d after images of changed rows to a log table. A better solution would probably be, to use the logical logs. Is it possible to get before and after images directly from the logical logs ? Are there other solutions how to log changes ? (must be done on the database level, not on the application level as we need to track all changes). Peter