Hi - I am using Civil 3d 2009 and to get around the fact that Impression and Civil dwgs don't work so great together, I am using a layout plotted to a 2D DWF6. Fills and strokes look great but blocks come in at a default style size of 9600%! Woah. My sketch scale is 1:1, on a D-size canvas. I tried a dummy drawing in plain ACAD. Pulling in the layout works as expected, but the same layout in DWF wacks out the blocks.
I hate to say it but it seems like a Bee.yoU.Gee.