If someone took a look at the file checking code (im sure you can freely download the software for filecheking) im sure it could be reverse engineered, im not sure why nobody has actually done this yet.
Sorry GIGI about sending you on the wild goose chase, but i tried that about half a year ago and it solved all my problems, I guess they have updated, I dont really play OFP that much anymore.
Edit: if you modified ALL the files in merged, on the file checkers it would bring up all the .paa files but as many people know the Russian version of OFP envokes this warning anyway regardless of weather they modified the merged, maybe you could do that and try to pass it off as a Russian copy?