Something like this...
viewtopic.php?f=29&t=4856poweroff the pogoplug, unplug thumb drive and data drive, poweron, plug in the 1GB and 4GB thumb drive and then mount them, then run the backup script
Edited: I think there is a simpler solution for copying
let say you mount the usb as sda1 and sdb1
then just
cp -ar /mnt/sda1 /mnt/sdb1