lightmaps for photoscenery ?

I've been building some VTP photo terrain using Sbuilder for use as airport backgrounds, and a couple ofther areas. I'm wondering if anyone has advice or example of how to make up a lightmap for this. A typical area would be maybe 3x4 LOD13s. I was thinking of maybe taking some default landclass lightmaps and blending those into my photo. For my immediate project 033b2lm or 029b2lm would seem to work. Any other ideas to avoid having a "black hole"?scott s..