Activating USB ports in a a VirtualMachine TOS installation

In order to have access to USB drivers of a Linux Host from a Virtual Machine (it could be vmware server or the SunxVM Virtual Box) you must modify the fstab file:
for a Ubuntu 8;10 Intrepid Ibex :
$sudo gedit /etc/fstab
Add these lines at the end of the file:

# USB for vmware/vbox and SunxVM VirtualBox
none /proc/bus/usb usbfs devgid=46,devmode=664 0

Ctrl+S (for saving)
restart the computer...
...

You can see then your USB ports available for use in the virtual machine

note:
Don't forget to give write permissions into the virtual machine TOS xubuntu installation:
$sudo chmod -R g+rw /dev/ttyUSB*