released a new version of his Arma 2 Game Launcher on the BI forums
You can view a video of this launcher here
Quote SpiritedMachine :
This program has been tested using all combinations of ArmA II / OA, beta versions, etc with success (Both purchased via Steam). However, with so many changes there are sure to be bugs. Please report any bugs you find either here or the project tracker. If you do report a bug, please try to give steps to reproduce the problem. Thank you
* External applications tab has changed to allow you to choose any application to run when starting ArmA II. Choose to start always, never, only for singleplayer, or only for multiplayer games.