There's an article in the November/December 2000 issue of Cook's
Illustrated re: the ultrafine sugar.
The article states the sugar weighs the same per cup as regular granulated
sugar and the two can be used interchangeably. I found it interesting,
however, that it is sold in 4.4 lb. bags rather than the standard 5
lbs. It further states that it is sold in supermarkets west of the
Mississippi, is available on the Web at http://www.bakerssugar.com/ and at
http://www.igourmet.com/ and from the King Arthur Baker's Catalogue.
Also to Phyllis, my substitution chart shows a substitution for buttermilk
is to place one tablespoon of either vinegar or lemon juice in a cup and
fill it to the one cup measure. I have used milk with a tablespoon of
lemon juice in my banana nut muffins many times and they are superb. I
don't even bother buying buttermilk anymore. I have no idea how this would
work mixed with rice or soy milk, but it would certainly be worth trying.