libvirt users - Nov 2013 - USB passthrough to WinXP guest - WinXP ignores it

WinXP ignores a USB passthrough!

Hello,
I need a persistent passthrough of a USB-device:

Bus 001 Device 020: ID 04e6:5311 SCM Microsystems, Inc.

I added  <hostdev mode='subsy....   </hostdev> like this
to xml file:

[...]
<on_crash>restart</on_crash>
  <devices>
    <hostdev mode='subsystem' type='usb'
managed='no'>
      <source>
         <vendor id='0x04e6'/>
         <product id='0x5311'/>
      </source>
    </hostdev>
    <emulator>/usr/bin/kvm</emulator>
    <disk type='file' device='disk'>
      <driver name='qemu' type='raw'/>
[...]


/var/log/libvirt/qemu/win-xp-prof.log:
====================================2013-11-02 12:26:42.007+0000: starting up
LC_ALL=C PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin
HOME=/ QEMU_AUDIO_DRV=none /usr/bin/kvm -S -M pc-1.1 -enable-kvm -m 512 -smp
1,sockets=1,cores=1,threads=1 -name win-xp-prof -uuid
5217ba2d-0d7d-1579-74a6-a1ad8439dda3 -no-user-config -nodefaults -chardev
socket,id=charmonitor,path=/var/lib/libvirt/qemu/win-xp-prof.monitor,server,nowait
-mon chardev=charmonitor,id=monitor,mode=control -rtc base=localtime
-no-shutdown -device piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2 -drive
file=/var/lib/libvirt/images/win-xp-prof.img,if=none,id=drive-ide0-0-0,format=raw
-device ide-hd,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0,bootindex=1
-drive if=none,id=drive-ide0-1-0,readonly=on,format=raw -device
ide-cd,bus=ide.1,unit=0,drive=drive-ide0-1-0,id=ide0-1-0 -netdev
tap,fd=20,id=hostnet0 -device
rtl8139,netdev=hostnet0,id=net0,mac=52:54:00:7f:d8:80,bus=pci.0,addr=0x3
-chardev pty,id=charserial0 -device isa-serial,chardev=charserial0,id=serial0
-device usb-tablet,id=input0 -vnc 127.0.0.1:0 -vga std -device
intel-hda,id=sound0,bus=pci.0,addr=0x4 -device
hda-duplex,id=sound0-codec0,bus=sound0.0,cad=0 -device
virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x5
char device redirected to /dev/pts/4

The enty seems to be ignored completely. Where is
my configuration fault?
Maybe extra module need to be loaded? - In installed
WinXP with virt-manager.

Host: debian wheezy, kernel 3.10,
libvirt-bin  0.9.12-11
qemu-kvm      1.1.2

tia
Ekkard

Solved: I forgot to call "define" to start the machine with
the edited : virsh define  xxxx.xml

I virt-manager I achived add "hardware" -> USB and added the
certain USB-device. After the xml was modified, but different
to my changements. Suddenly I remembered to call  "define"

:)