Hey, Mark - exactly what I wanted to do!  Had a little trouble until I realized I had to make a new texture to paint on the shader, but then it worked.  I used red for a border with some trees, left the wooded sections white, and painted the mountain and underwater sections black.  Worked great!

Thanks!

Lotus 123 ~ S-Render ~ OS/2 WARP ~ IBM 8088 / 4.77 Mhz ~ Hercules Ultima graphics, Hitachi 10 MB HDD, 64K RAM, 12 in diagonal CRT Monitor (16 colors / 60 Hz refresh rate), 240 Watt PS, Dual 1.44 MB Floppies, 2 button mouse input device.  Beige horizontal case.  I don't display my unit.