Hi there phuongtam,
The BT hubs are unable to assign more than 1 IP to any device, what you can do is you wan the Sonicwall rto manage the static IP's is to put the BT router into bridge mode, then setup the Sonicwall up to do the PPPoE authentication for the line, then configure it with the static IP range for your line that you want it to manage.
Markp