Rebuild Fedora 19 ISO adding Kickstart for USB install
i guess it is because you have chosen a new Volume Id by -V "NewFedoraImage".
I am the developer of xorriso and have experienced a similar problem when experimenting with GPT enhanced isohybrid in Fedora-LiveCD.iso. It did not work unless i used the same -V as with the original image. In an old mail text of mine i see a reference to "/dev/disk/by-label/".
To learn about the original Volume Id, you may do:
xorriso -indev Fedora-19-x86_64-DVD.iso 2>&1 | grep 'Volume id'
(Leave out "2>&1 | grep 'Volume id'" if you don't get any output)