A solution to this problem has already been created on this site.  Search the script section with the keywords triggers and (generated, concatenated... sorry don't remember the name).

Basically it's a script that creates an audit table for each table in the system.  It also creates the trigger that audits the data.  I don't remember if it creates only the code or if it generates the objects as well.  But it was working great as far as I remember.