If you want to access them in pylons.config then you want to put them in the [app:main] section of the configuration.
I've used turbomail, and then you can put them in [DEFAULT]. This is what my config looked like.
[DEFAULT]
mail.on = true
email_to = toaddress@domain.com
mail.manager = immediate
mail.transport = smtp
mail.provider = smtp
mail.smtp.server = smtp.domain.com
mail.smtp.username = username@domain.com
mail.smtp.password = passwordhere
error_email_from = paste@localhost