The package maker delivered as part of the developer tools for OSX 10.5 is awful. Just doesn't work, go see the
mailing list archives for a world of pain. Thankfully there is an alternative:
Iceberg has a weird UI (add files to the package by right clicking where you want them to go then selecting "Add Files") but builds installer packages that work and appear to have
all the features of a "proper" Apple package. Even better, an Iceberg project can be built off the command line - and hence in the "Run Script" build phase in XCode - just by calling "freeze" and passing the name of the iceberg project. Love it! Thank you, Stéphan!