There's a quick and easy method of installing WattOS (or any Ubuntu derivative) from a pendrive: isohybrid.
It's a tool which is part of the syslinux package.
just install it, then type
where FILENAME.ISO is your iso file. The md5 checksum will change, of course.
Then, you can just write your modified iso file to a pendrive:
sudo su umount /dev/sdx
where sdX is your pendrive device name. Pay attention!
dd if=FILENAME.ISO of=/dev/sdX sync
I think all WattOS ISOs should be patched with this. Or maybe they are and I didn't know it?
Hope this helps
Thanks to you. R4 works great on my EeePC 900 :)