I forgot something, Virtual Box OSE does not support USB devices..You might want to use the Oracle Virtual Box. If you boot from CD live, I'm sure it will be recognized, but don't know if your device is aircrack compatible...
Here you can read this that backs my assestment, by the way, I use Oracle VM, it has usb support in my debian. Debian squeeze has the OSE and had to change it.
and this one:
I use Debian Squeeze, stated that OSE does not support usb, if you want switch to Oracle Virtual Box. I'm affraid BT5 is using OSE.
Here is another thread, read it, please:
Also read the Oracle VBox homepage.
Also google on this matter, you will see.
You would have to install on Hard driev BT5, uninstall Virtual Box OSE (aptitude purge), download Oracle VB (it installs the pack including USB support).
I updated the squeeze repos and added the Oracle "deb" to install it from repos"..All that is in Oracle Page.
Best of lucks.