Marketpress local time on new order email

WP 3.4.2 > MP 2.7 > Twenty Eleven Theme

I've have done some testings and research. The problem is that when a new order is created, the local time stamps on the order details shows the time in the wrong timezone. I have set the zone correctly in both WP and on my server (America/Los_Angeles).
I found half of the solution in the Community section. I added date_default_timezone_set(get_option('timezone_string')); at the beginning of the marketpress.php file and that fixed all the time stamps except on the notification emails sent to the customer and the admin.
I have tested this on my live site and another site on another server with the same results.
I have disabled all plugins on the test site and still the same problem.
Could you please tell me where can I force the timezone on these two email notifications?
Thank you,
Leticia