Patching question

Good morning everyone.

I didn't know where to go with this so being that I used to multibox in the past, I thought i come here.

I have two accounts these days. One is a regular US account with folder stored under c:/worldofwarcraft.
Second is a German account that I use to learn the language with with separate folder stored under g:/worldofwarcraft.

The problem i encountered is that i am unable to patch the second folder to 3.1.
Both patches downloaded beautifully...the German being slightly bigger that the US one.
The US instance of the game updated with no problems.
Now, when i try to run the European Wow, I get a warning telling me that the wow.exe file is already patched up to 3.1 and there is no need to do anything else.
So i moved the European 3.1 patch to g:/worldofwarcraft and tried to patch it there with same results.
My next step was to rename us folder, us wow.exe and launcher.exe to something else and trying to patch European wow again.
This time though, i got an error message that the wow.exe could not be found.
It seems to me that even though I try to patch it from somewhere else it still tries to look for the US version of the game/exe file.

Would any of you have an idea how to patch my european version of the game without deleting/reinstalling my US version?

Thanks