UCK has several utility scripts to allow you a flexible remastering, here you can find the complete list (in logical order):
Usage:
# uck-remaster-unpack-iso iso-file.iso [remaster-dir]
Usage:
# uck-remaster-unpack-rootfs [remaster-dir]
Usage:
# uck-remaster-unpack-initrd [remaster-dir]
Usage:
# uck-remaster-chroot-rootfs [what-to-execute] [remaster-dir]
Usage:
# uck-remaster-prepare-alternate [remaster-dir]
Usage:
# uck-remaster-finalize-alternate gpg-key-id [remaster-dir]
Usage:
# uck-remaster-remove-win32-files [remaster-dir]
Usage:
# uck-remaster-pack-initrd [remaster-dir]
Usage:
# uck-remaster-pack-rootfs [remaster-dir] [-c|--clean-desktop-manifest]
Usage:
# uck-remaster-pack-iso [iso-file-name.iso] [remaster-dir] [-g|--generate-md5] [-a|--arch=x86,x86_64,ia64,ppc]
Usage:
# uck-remaster-clean [remaster-dir]