for the eng keyb layout try "klinux lang=eng", for sdb we should change the partition that the boot process search for , actually it's sda1 , i'll made one for sdb1 too.(soon probably today )

>How can I achieve to habe the USB drive mounted as RW (persitently)?

i really don't know .... i hope someone will help you ....

*PS: general: for someone was helpfull "klinux acpi=off"