All you need to do is zone into Black Temple. Just did it a few minutes ago. I'm on US servers if it matters.
https://i.imgur.com/ONDg8.jpg
UPDATE: I finished Black temple and hearthed out. The achievements disappeared from my recent achievements list but the points still counted it seems. The Black War Bear mount was still in my mailbox also. Very weird.
Pic update w/ time: https://i.imgur.com/MZZFE.jpg
After reading nmsae's comment, it sounds like he's right:
"It's practically the same exploit as the Challenge Conqueror exploit, so you need to disconnect during the loading screen to receive the achievements. And you need to have the achievements on another character to be able to obtain them."