Here you go, Doug. This is a nice technique to know, because you can use it to easily create other type of local scenery changes such as Population Density and Seasons, as well as Regions which I'll cover here.
You do need to have SbuilderX and the FSX SDK installed though.
First, in SbuilderX turn on the Background image (Virtual Earth Satellite is the only one which works reliably for me) and go to the area you want to change.
Find out the Region number you wish to apply. In this case I'm using Region L (European French) so the value is 11 (I think.)
Open the Landclass tool, and select Landclass 11. Yes, I know we don't want Semi desert landclass, but it's just the value we are after. There are some limitations here, in that you can't select LC 0 or 1, some people use the waterclass tool instead if they need value 1, if you want zero you are out of luck. However it is possible to get around this, if you ever need to do this I'll show you how.
For large areas, use the large brush size (7x7=49) otherwise choose a size to suit, and 'paint' the landclass value over your background. The only important point is that you shouldn't go outside the photo scenery area, otherwise you'll get strange landclass displays around the edges of your scenery.
Once you've painted the area, exit the landclass tool, select the landclass tiles, and press the 'BGL compile' button.
Don't select the Copy BGL files to BGL folder button.
Now you can exit SbuilderX. Find the SbuilderX working folder. (SbuilderX313\Tools\Work for me.)
You'll see three new files -- a bgl, which can be discarded, an inf and a raw file.
Open the inf file in Notepad. It might look like this:
Type = Raw
SourceDir = "."
SourceFile = "LC_9446.raw"
Layer = LandClass
SamplingMethod = Point
SampleType = UINT8
NullValue = 254
ulyMap = -39.375
ulxMap = 172.5
nCols = 257
nRows = 257
xDim = .0146484375
yDim = .010986328125
DestDir = "."
DestBaseFileName = "LC_9446"
DestFileType = BGL
UseSourceDimensions = 1
All you need to do is to change the Layer = Landclass to Layer = Region. That's all. Now drag the inf file over Resample.exe and it'll create a Region BGL. You can rename this to something more useful, and drop it into your Scenery folder. All done.
I've also used this to make local PopulationDensity files to increase the number of pleasure boats (the value is a percentage, so 50 gives a good number of boats at a popular tourist spot), and even Season files although these are trickier.