I'm using my 3rd Party Developer and 3rd Party Installer certs to codesign an app bundle and then the package for that app for non-MAS distribution. Both operations report success and running "codesign -vv /Applications/application.app" reports:
/Applications/application.app: valid on disk
/Applications/application.app: satisfies its Designated Requirement
However, when I transfer the PKG file to a server and then download it onto another system, Gatekeeper tells me that the app is from an unidentified developer. I have verified my certificates in Keychain Access and they match what is included with my developer account on developer.apple.com.
Anyone have pointers as to what to check next?