还有人记得吗？以前是通过快捷方式启动OA？还是有一个单独的exe？
搜了一下官方wiki，好像也没有如何在steam版整合的方法
倒是找到个快捷方式的启动参数，留着备用吧
https://community.bistudio.com/wiki/Arma_2:_Startup_Parameters
These parameters can be configured by creating a new shortcut on your desktop and then adding the appropriate option in the target line.
For Steam version:
Choose the game shortcut in Library
Right click on the game
Select properties
Hit "Set launch options"
Example"C:\arma2\arma2.exe" -nosplash -mod=test;x\test;c:\arma2\test2

刚才眼瞎了，oa文件夹里有个 _runA2CO.cmd 可以了