Yep, the range function wimps out on you right when you need it the most. Their excuse is that you should add fuel as soon as possible after the warning light comes on, but most other manufacturers seem happy to provide you with trip computers that count right the way down to 0 miles (and still have some fuel in reserve after that.)
If I see it coming, I tend to check the current MPG and range, and do a quick mental calculation of the number of gallons I have left. I then switch to the 'gallons used' display and either reset the trip or add on the figure that I came up with.
By rights, you shouldn't have to do that, but if you can be bothered, it does work.
I should add that I once ran my 2.0
dry while trying this trick. According to my calculations, I still had fuel left (less than half a gallon mind you) but the
still threw up an injection fault and the car spluttered to a halt. I don't think I got my sums wrong, so maybe the computer just isn't that accurate.