Items are prioritized in Aha's release area by the Product Manager. When sending the release to Pivotal Tracker, the Stories that appear in PT are in reverse order, meaning the engineering team must spend time comparing lists to fix the order.
I expect that when I send my release backlog to PT from Aha, that the items appear in the Icebox in the same order (highest priority first)
The fact that rank order isn't preserved when creating stories in PT is brutal. As Stephen suggests creates a ton of administrative overhead to using the integration.