As it turnes out you need VirtualBox non-free in order to get USB support. Bah.. That’s one wasted hour trying to activate USB support in the free edition you find in Ubuntu’s repositories.
Once I figured that out it turned out to be really easy. Just append this line to /etc/fstab
none /proc/bus/usb usbfs devgid=46,devmode=666 0 0
… and install the non-free edition from http://virtualbox.org
Tags: Ubuntu Virtualbox