Please help me understand the pinouts. Take a look at this link USB pinout.

The N800 has an USB mini connector on the side under the stand (third image from top on left side). A USB peripheral like a flash drive has a USB male "A" (top image on left side). So the adapter must have a mini B male on one end and a full size A on the other right?

Is it grounding the 5th pin marked "x" in the diagrams that tells the N800 to go into host mode?

I think so according to http://en.wikipedia.org/wiki/USB_OTG
David