How to enter wifi password without wifi connection

[Dlass]

I'm getting a Mac ready to install at other sites. I would like to prepare it by having the wifi names and passwords for those sites already entered. But as far as I can see, the only option for entering a wifi password is if that wifi network is locally available. Maybe you can do this in Keychain access, but it sure isn't obvious how to do it. Ideas?

 

[MacsBug]

You would need be able to log into the WiFi network in order to add it. Its not possible to add a AirPort Network record to the keychain manually that I know of.