change password in OWA with UPN

Hi there!

All of you know the reg key to set to enable the feature that will allow users with expired passwords to change their password (orchange password at next logon).
http://blogs.technet.com/b/exchange/archive/2010/10/06/so-you-want-to-change-your-expired-passwords-in-owa.aspx

On Exchange 2013 this key is set oob.

On Exchange 2010 SP1 RU3 this works fine with UPNs.

But on Exchange 2013 some of the old Problems are back! I am not able to change the Password while using UPN Logonname. Its not a Problem when using the pre-win2k logon domain\username.

UPNs still work fine for normal OWA logon.

Is there any way to resolve this issue?
On OWA virtual folder i set form based authentication to UPN.

Thanks alot and sorry for my english skills ;)

Garfield