Hi
I've been playing around with this kind of solution also. I haven't had any luck.

You gave me the incentive to try yet more more time via my external powered hub.

It doesn't work. It's even worse that that. I have one of the OTG adapters and when I plug in my 1GB usb flash key directly everything is fine. I can read and write to it. When I put the same lash drive in via the powered hub - nothing - nada.
I had bought the externally powered hub to get my 2.5" drives working as above but a great idea down the tubes when nothing worked (Bun - we talked briefly in another thread a week or so ago about this). But it seems the problem is in the hub itself. It works fine as advertised on both my linux laptop and desktop but not on the NIT. I tried your trick by starting from power off but no symbol - nothing. So I guess it is the brand of powered hubs??? Mine is called "4 port slim hub" - model UH-374AP
http://http://www.sigelectronics.com/PC-Mac-Hardware/Computer-Accessories/UH-374AP-USB-2-0-4-Port-Hub
So I guess it also has to do with the type/manufacturer. I guess it off to buy one of yours... Really need this for my camera when I travel.

C