Install Session from USB?

[m3bik]

Lets say I install a Live CD iso onto a USB thumb drive, therefore creating a portable operating system. I know I can save my session data on the USB so I can access it later.. but what if I want to install the os and session data on to the hard drive?

Ex: I have a "Live" version of Ubuntu on a USB drive. I add the file /usr/src/myfile that is saved on the thumb drive (using persistent file storage) so every time I boot from the USB drive, that file is still there. I would like to be able to click the Install button from the USB Live environment to install Ubuntu onto the hard drive and copy this file over during the install (vs having to manually copy it over later).

In a sense, it would be like creating my own install cd.. but this seems like it would be a lot easier?

[m3bik]

Is this not possible?

[TBeholder]

Isn't it the same?
I used installation CD image in "Startup Disk Creator" recently. It proposes to install, then its "test" mode runs just fine. It's probably possible to find and disable the "install" menu on boot, while keeping the shortcut for installation and everything behind it.

Or do you mean one Flash with grub set to Live-"CD" and more normal system on another partition?