Imported From: http://groups.google.com/group/in-portal-dev/browse_thread/thread/7858ae78b7ed9534#
Hi guys,
i've just discovered that, beginning with 5.2.x, when you place an order, email confirmation is sent twice: once to account email, once to billing email.
It doesn't seems to be a bug, because these 2 address could be different, and I suggest that billing email (and all other billing fields) could be pre-populated with user account details, by default.