Friend emailed this to me, said he got off another site, unconfirmed since I haven't got a high level char to test with atm.
1. Get your lowlvl Char (from lvl 11) into the Warsongqueue (11-19)
2. Quit WoW (don't log off - ALT F4 out of the game)
3. Start WoW
4. Try to login with your lowlevel char - "Charakter already exists" will appear
5. Login with your Highlevel Char then
6. After a while "Join Warsong" will pop up
7. With a little bit luck you entered the lowlevel Warsong with your highlevel Char