Go in the i18n folder, and copy the different properties files (for example gui.properties, etc) somewhere else. Adde them a _ru (for example, gui.properties becomes gui_ru.properties, etc) and put them back in i18n (of course, save the original _ru ones somewhere), and your game will be in english (I made it for French using the _fr ones).
This made, loading screen will still say that you are in RC4, but this is not very important (to me at least...).
Other problem is that even if the game loads without problem, when I launch a QMB mission, it loads up to 100 %, and nothing more. I have to "kill" the game, forcing it to stop with the task manager. Or, if with some planes, the mission loads and is playable, it is when I want to go out of it that the same problem happens... seems the ModAct is not 100 % ready...