I have used a 4 port USB hub and fitted it to the host inlet.
I also purchased a Wii lan usb adaptor.
It seems that when you channel the lan through the hub it blocks all signals from both a wired and wireless keyboard so as there is no OTG inlet, it is likely that even if you can get a 3g dongle to work, it will block the mouse controls.
As soon as I plugged the lan usb adaptor into the hub, the mouse pointer disappeared off screen.
If anyone can throw any light on this problem, it would be appreciated.