How to use usb device in virtualbox ??

In the last post ‘如何在visualbox使用usb device?‘,
I mentioned that I need to change to udev rule file in order to use usb device.
After some researches, I found that I don’t have to modify this file.
But I do need to modfy some init script file in order to let virtualbox to use usb devices.
The file is /etc/init.d/vboxdrv.
Edit this file.

-mkdir -p -m 0660 /dev/vboxusb 2>/dev/null
+mkdir -p -m 0750 /dev/vboxusb 2>/dev/null

Now remove the vbox directories in /dev

sudo rm -rf /dev/vbox*
sudo /etc/init.d/vboxdrv restart
# must stop and start, if only use restart, seems nothing happen.
sudo /etc/init.d/udev stop
sudo /etc/init.d/udev start