Copied from wow-europe:
On your account page:
1.Go to Games&Codes - "Add or upgrade a game" (slect any game, Wow for example, click buy now) and change reagion from "You will play in: EUROPE" to AMERICAS & OCEANIA (you ofc dont need to buy anything)
2.Now go back to Summary page and add STARTER EDITION
it will be shown as additional transparent button at the bottom of your WoW list:
World of Warcraft®
Americas & Oceania (US) PLAY FOR FREE
(You should now have additional account under Summary
World of Warcraft®
[WoW1] (Starter Edition)
Americas & Oceania (US)
3.Click on your Mists of Pandaria BETA account icon
4.Click on "Beta Character Copy"
5.It will offer you to copy chars from 2 accounts: your original WoW account and this new one we created (Started Edition - Americas and Oceania) Select that one.
6. Select Premade chars you want copied and select any server including EU one.
Chars will be copied almost instantly.