Just a small technical quibble--it matters not that this fellow can't actually get to his asteroid...governments tend to adjudicate property rights over a lot of intangibles (intellectual property being the most obvious case).
I've been reading your blog quite a bit lately--basically, although Norway is nice for postcards, it leaves a little to be desired in the excitement department.
NORWAY? What the devil are you doing in NORWAY? Is that general strike we heard about over with yet?
Anyway, I based my argument on historical example, namely the experience which America had back in the early 19th century. The short version of what happened then was that the Government was forced to legalize squatters' rights over previously-undeveloped property out West, letting those who developed it purchase it for a minimal sum. I think we'd see the same thing in this instance -- and with the AMOUNT of potential real estate out in space, the price would likely be cheap, at least if the only available resource on or under it was dirt.