How do I sign a Mac App for distribution outside the Mac App Store

Hi,

I'm trying to sign a Mac AIR application, so that users do not need to change their security settings in order to install it.

On Apple's developer portal, I created a Mac "Developer ID installer" certificate which I downloaded and installed into the Mac's keychain

Looking in "Keychain access" under certificates I have a certificate called

Developer ID Installer: Victorian School of Languages (22F6M8ZTB3)

Which I tried to export and use to sign the Mac App installer. but this certificate does seem to need a password to export and is not compatible with AIR for creating the installer

Is there a documented process to sign a Mac app using our developer certificate, as we can't distribute our app though the Mac App Store, as it uses Adobe's own internal webkit (and doesnt work if we switch to using the native webkit (for StageWebView) as require by Apple for Mac App store submissions

Thanks