If set filter driver under USB bus, can't find

Hi,

I set my filter driver under usbhub.sys, but even if the USB printer
is pluged, Win2K can’t find the USB printer.
After Irp is called with IRP_MJ_PNP and IRP_MN_QUERY_DEVICE_RELATIONS,
Pnp process stops. I guess no informations may return.
Can any one trace the data under the USB bus ?
Is the filter driver valid only over the USB class driver ?

Thanks,
Yasushi Inaba,
7/28/2000