How to switch between OA CD-Keys?

[Vladdie]

I bought a second copy of Combined Operations from BI's website for Steam so I could have two characters on DayZ (as my brother can't play as much as me so I need an alt to play whilst he is away) but now I appear to be stuck with the new character (as I assume the Arma 2 cd keys were changed in the registry when I opened the Steam version (my original copy is retail).

So I need a way to easily switch between the two cd keys or have some way to stop the two installations (retail and steam) to stop conflicting with eachother and I can easily play on either. If I switch back to my old cd key will my old character come back, or is that one lost?

Thanks!

[Placebo]

Have you tried creating two different windows logins?