De esta resposta, eu tenho os detalhes abaixo.
I have fixed this issue using "USB over Network", from here. You can easily download the server, install it to the XenServer and then install the client to your VM so you can share the USB devices connected to your physical server to your virtual server.
This works with almost all devices you can imagine. I have even tried to use a webcam and this worked flawless.
Verifiquei a seção downloads e eles têm para o servidor Linux / clientes.