[libvirt-users] Attaching usb devices

Is the only way to attach a usb device to a vm first specifying the device, <hostdev mode='subsystem' type='usb' managed='no'> <source> <vendor id='0x3080'/> <product id='0x1234'/> </source> </hostdev> and then booting the vm while the device is attached? Can't I attach/detach a USB device to the vm later? I did try the method suggested in http://david.wragg.org/blog/2009/03/usb-pass-through-with-libvirt-and-kvm.ht... but did not have much luck. Also, can anyone explain me what happened in this log excerpt: husb: open device 1.18 husb: grabbed usb device 1.18 husb: config #1 need 1 husb: 1 interfaces claimed for configuration 1 husb: device 1.18 disconnected