After Trigger effect in SQL Server 2005 transactional publication

On publisher table P1 we have after trigger on last_update_time column which is fired when any data is updated. On subscriber table S1 we have an insert trigger to audit all the data changes into audit table SA1 . When any data is changed on P1 2 records are inserted into SA1. 1) The data change. 2) update last_date_time data which is the result of after trigger on P1. How can I manage to audit only one record on SA1 for any change on P1 including last_update_time column.