Sorry, you can't import that under any circumstance.
Once released under CC BY NC SA 3.0, you cannot rerelease it under different conditions. Add onto that that TVT policy is that you surrender any rerelease rights once you post it, and that makes it even worse.
Legally, we have no idea if their license change or any of their new content release policy effective end of June 2012 onwards was/is legal, but we absolutely refuse to take chances since it would require visiting a courtroom to decide, so I'm afraid we can't allow that.
Those articles can be recreated from scratch here, but any deliberate plagiarism of content under a different license (even that which you originally wrote) is not acceptable.
I'm sorry if that sounds harsh, but it's ATT policy that we refuse to violate copyright law, even if we're not sure if it is legally considered such given how TVT changed their license and content policy.
Basically, we're not taking chances.