Trigger and Permissions

Hello, ALL

I'm making a simple log system where all the users (each one have a
different login and password) will be logged all your actions.

When a user delete, insert ou update any data in a table, the trigger
will log the operation in another table.

Until this point, all OK. I made this trigger and it's work fine.

But the log table must be writable for all users !!!!!!!!!!!!!!!!!!!!
Instead the trigger can't write into the log table.

It's not nice, because the user can simulate a log......

THE QUESTION::::

How can I make a trigger that insert data in a table that no normal user
have INSERT PERMISSION ?




Regards,


Tulio