Have the issue of having the Mist of Pandaria on your account but only seeing the Test Realms and not the actual Beta realms?
Here is a fix for the issue!
Login to your battle.net account and add a standard starter edition (Free) account to your battle.net.
Once you have done that check to see if you have the 'Select Account' Option on the NORMAL WoW client. You should see WoW1 and WoW2
If you have try and login to the BETA Client. - When it comes up asking which WoW you would like to use, Select WoW2 you should now be able to see different realm names E.G: Mekkatorgue(EU) ect.
This has worked on 2 of my accounts so far.
I will add that i am on EU.