Flat Packages, Gatekeeper, and Resources

Hello.

This is a cross post because I could not delete my old message in "Mac OS X Technologies" subforum. Apologies for that.

I am maintaining an old 10.4 style package which is a bundle (or distribution package?) produced from package maker 3.0.4. Since we now need to sign our packages and since this requires, it seems, flat packages, I took my existing package and set the minimum target OS to be 10.5, which converted it to a flat package. Thereafter I could sign our package using productsign. However, the readme, welcome and other files stopped being displayed during the installation process. These file display options seem closed to me:

http://developer.apple.com/legacy/mac/library/#documentation/DeveloperTools/Conc eptual/SoftwareDistribution4/Managed_Installs/Managed_Installs.html#//apple_ref / doc/uid/TP40004615-CH6-DontLinkElementID_29

So my questions:

a) Is there are way that I could re-incorporate them (readme, welcome, etc) into the user experience and sign my package so that Gatekeeper will not complain?

b) Is it true that only flat packages can be signed?

c) When I select 10.5 as the minimum OS, the postflight option disappears from the UI, but it still seems to execute. Why? Should I switch to postinstall instead?

d) Are postupgrade and preupgrade valid for flat packages? Or is there no difference between postinstall/upgrade and preinstall/upgrade?

e) Are flat packages and distribution packages fundamentally different?

Thank you for any help, I do appreciate it.