Okay, then simply release the lightmapper!

Honestly, I still build my models in MED!
I start with a small terrain, let's say 8x8,
then I add a texture,
then convert it to mdl,
build blocks out of this plate which give the rough shape of a canyon or whatever gives the natural environement that I try to achieve;
after that, I connect the plates,
and deform their blocky shape to get more stony and scarp-like shapes...

This means that I have all the surfaces that I use in the 3D-part already unwrapped in the uv-map, I simply have to scale them down and place them side by side on the skin map - and therefor all I need is a lightmapper, because I can't export and import the mdls to and from another tool where I make the lightmap!