Gatehouse map in CC2 (no doors)

I've completed the gatehouse map in CC2, but haven't added the doors yet (I'm not happy with the default set of symbols DD2 provided, so I'm going to make my own over the next few nights).

It turned out to be very very easy to draw the dungeon.  BUT, it is very very painful to draw that gray background.  It's a very convoluted process that involves copying and "exploding" and splitting elements to come up with the reversed-polygons.  I'm not looking forward to doing it on the first level map.

So here's the map done up in CC2.  Click to see a larger version.  The graph paper lines got distorted when Photobucket resized the image, it all looks very nice on my computer, and should look perfect in the PDF as well.

And here's the original pencil drawing on graph paper: