Hi Chad,
I still can't make the tracking work on a second portal. The mail seems to send the correct URL which is in this example:
src="http://www.saludperfecta.com.mx/Contacto/OptInMail/tabid/188/Track/True/Opt-In-EmailID/315130eb-82ce-4261-bb1a-e610f92d7790/NewsletterID/17b8b23b-d5ff-431b-84e0-ca0c9a88c95d/Default.aspx"
But the mail does not show the 1x1 image therefore not tracking the emails.
Thanks.