The 64-bit version of Wilbur should be able to handle the full resolution map if you're patient. The 32-bit version definitely works with 4k by 4k maps (again, if youre' patient).
Ralf Schemmann wrote a tutorial on getting data from CC2 into FT. If you stop a step early then your map will be in Wilbur. See http://www.jhendor.de/tutorials/cc2-ft.pdf for the full tutorial. The basic process is to set each contour level to a color ranging from black at sea level to white at the highest point and then load this image as a surface.