Just a fast way to get the model with a second uv-map:

Save the model with its name and an addition like _lm,
then click through the skins and groups in the Skin Editor
and change the skinsettings, that all parts of the mesh share the texture of the first one,
choose all, and scale them down to the tenth or so of the skin texture
(maybe, you have to do this several times switching from group to group etc.),
then switch to the 3D Editor and choose a single triangle of that side
that you want to be mapped in the upper left corner of your lightmap,
(Options -> Sync Skin Selection must be checked)
switch back to the Skin Editor and click Select connected,
move that part of the uv to the upper left corner,
switch to 3D Editor again, choose the next part which you want to line up the first one
etc. etc.
Save the model again.


@DavidLancaster : From my photographs, made seamless in the Seamless Texture Generator.