You can use SBuilderX version 3.15 to do this by drawing vector lines on either of several imagery tileserver backgrounds in the work-space.
Since you have already used Google Maps imagery via the Desktop Edition of Google Earth (aka "GE") to draw vector poly-lines as "Paths", you should save the Google Earth 'Path' object as a *.KML file format.
Then convert the *.KML to a *.BLN file using rhumbaflappy's KML2BLN utility:
I suggest that you first review this tutorial by Luis Feliz-Tirado:
Terrain Design for Flight Simulator X
This simple illustrated document explains the basic concepts in Flight Simulator X terrain, and how to change them using SBuilder for FS X. Make new water bodies, roads, vehicle traffic, airport flattens, remove autogen, add more detail - anybody can do it easily and quickly.
My most sincere apologies - I am unable, for lack of free time, to offer support of any kind. For questions or problems, please post in the Avsim scenery design forum.
Filename: terrain_design_for_flight_simulator_x.zip License: Freeware Added: 14th December 2009, 13:29:15 Downloads: 16648 Author: Luis Feliz-Tirado Size: 3991kb
After the *.BLN is Appended, one can copy & paste the GE 'Path' object within the SBuilderX workspace.
One copy of your GE 'Path' object can be edited as a poly-line only; this may be assigned as a shoreline. Finndo: And this should be as I have drawn a coastline?
The other copy of your GE 'Path' object can be edited as a polygon only; this may be assigned as a water body. Finndo: Water body??
In SDK TMFViewer:
[Microsoft Flight Simulator X SDK install path]\SDK\Environment Kit\Terrain SDK\TmfViewer.exe