Move retail copy of Arma 2 to Steam folder

[johnabcitizen 10]

My problem is quite simple. I have a retail DVD copy of Arma 2:CO. I have installed it from the DVD. Is there any way to copy the retail game files over to the Steam folder to avoid me downloading 15GB+ of data over Steam when I active it with the CD key? I live in Australia and our internet is worse than Mongolia's, so 15GB would be about half of our total monthly usage and incredibly slow.

I've scoured these forums and the internet for half an hour, but no luck. Any help would be greatly appreciated.

[Joe98 92]

I have the same slow internet in Sydney - in Joe Hockey's electorate - and have the same question.

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