To enable Reminders Importing, go into "Settings" and tap on the "Siri & Reminders" row. If you do not see this row, then it means that your phone does not have Siri. Only the iPhone 4S and iPhone 5 have Siri.
Tasks imported from Reminders do not inherit the task defaults yet. This is on our to-do list.
I have an iPhone 4s on 5.0.1 with fully functioning uk Siri but that row doesn't show up. I too stopped using Toodledo as it wouldn't work with reminders so I'd really like this to work. Any idea why my Siri row isn't showing up in settings?