If you are using a powered hub, there should be no problem. Each port in a powered hub has full power to draw from.
If you are using an unpowered hub it will depend on how many other devices are attached to the hub. An unpowered hub only has the one ports worth of power available to it. Devices plugged into an unpowered hub share the power and therefore may not function properly if at all.
For optimal performance plug your Attaché either directly into the computers USB port or use a powered hub.