Do ARD Create client installer packages work with InstaDMG?

I've created a custom client installer package to create a user and configure ARD, but it doesn't appear to work. The InstaDMG log shows the package being installed, but after booting up the imaged system, there's no ARD user. Remote Management is enabled in Sharing, but there's no user with management privilieges. The package works fine if it's installed manually on the client. Am I missing something? ARD 3.3.1, Mac OS X 10.5.8.