CentOS virt - May 2009 - Dynamic XEN USB usage for Win Guest?

Hi,

I am trying to attach a Palm Z22 via USB to my fully virtualized Win XP.

Dom0-System: CentOS 5.3 x86_64 (Kernel 2.6.18.128.1.10.el5xen)
XEN: 3.0.3-80.el5_3.2

XP: 32-Bit Professional

lsusb shows:
USB Palm: Bus 002 Device 007: ID 0830:0061 Palm, Inc. Lifedrive / Treo
650/680 / Tunsten E2/T5/TX / Zire 21/31/72 / Z22

I found some hints that I have to put

usb = 1   and
usbdevice = "host:0830:0061"

into my DomU-config.

When I start the DomU without the device switched on I get (qemu.log):

Warning: could not add USB device host:0830:0061 I/O request not ready:
0, ptr: 0, port: 0, data: 0, count: 0, size: 0 I/O request not ready: 0,
ptr: 0, port: 0, data: 0, count: 0, size: 0 Triggered log-dirty buffer
switch

When I start the DomU with the device switched on I don't get this error
- but the usb-device does not appear in XP.

Questions:
- why does the device not appear in XP?
- is there a way to dynamically attach the usb-device (it is not present
the whole time!)?
- in the CentOS documentation abot xen (virtualization guide) I found an
option "usbport" but I have found no exaple on how to use it - would
this work instead?

http://www.centos.org/docs/5/html/5.2/Virtualization/chap-Virtualization
-Configuration_files.html search for "usbport".


Kind regards

Nils