Hello,
I was also trying to do the same as Domminust, except that I'm trying it with 1.12.1 version, so the files provided in this topic cannot be used. I started to slowly discover stuff myself, step by step.
I successfully swapped the background image behind the Dark Portal, but now I got stuck with editing the .xml files. I extracted the 1.12.1 files from patch-2.mpq of 1.12.1 and for starters I tried to move the Blizzard logo from the bottom to the top of the screen (inside AccountLogin.xml).
Sadly, everytime I make ANY change to the .xml file and pack it into a patch-i.MPQ file, the game gives an error (Interface files are corrupt, plz reinstall the game). I thought maybe those are not the correct interface files, so I extracted the default files from patch-2.MPQ again and packed them into a new patch-i.MPQ file without any changes inside + I swapped login screen music. The game works with different music, so my patch file also works.
Can you tell me why it won't allow me to do any changes in the XML file?
Thx in advance.