in the zip, there SHOULD have been /fs/data/.firstboot into which you place whatever apk files named according to their actual package name i.e. com.keramidas.TitaniumBackup.apk for Titanium Backup, com.alensw.PicFolder.apk for QuickPic and so on...
you can find out this info in Titanium Backup by finding the app in the list and tapping its name to show the data store location.
it HAS to correspond to the actual package name in order to properly back up the data files because the package manager binary as run from a script won't overwrite the data dir so the old data has to be synced back into the new install (rsync)
I am currently refactoring the script to reduce the number of dependencies... the system will then consist of the init.d script, zipalign and rsync bins, and the /data/.firstboot.sh, /data/.firstboot dir all in one place rather than scattered throughout the system.