I think the ru localization is the problem here.
The Localization files are tied to the exe, and I did not find a proper changing method yet. So you would need the Complete English LocData specifically, plus a slightly changed default.cfg file.
I can supply you with both of these, gimme some minutes.
EDIT: Here you go:
https://openload.co/f/cZ1xReolgYI/SW...h.LangPatch.7z
Just install this first, and then re-do the installation for the expansion mod. This should work.
If it still somehow doesn't, I would have to do some more research about what files are affected by language.