update an existing APTonCD iso

The ability to easily update or modify an existing APTonCD iso would be useful. Such as a case where one has a basic install iso configured and then wants to modify it with updated, fewer or additional packages.

An existing open-source software, ISO Master has the functionality to directly write to the iso image, so perhaps the source of this application would be useful. http://littlesvr.ca/isomaster/

Perhaps a simpler route may be to create a list, such as with the existing feature of synaptic, but have a GUI to modify the list as a meta-package. Users can also easily redistribute these meta-packages (very small filesize) as kinds of popular Ubuntu configurations to be used or modified by APTonCD as the user sees fit.