Thanks Shambler - your second solution isn't really what I'm looking for, since it doesn't use a second independent set of texture coordinates.
Basically I want to do a very simply example of light/shadow. I thought I could use one set of vertices for one texture (using VertexTextureCoords) and a second set of vertices for light/shadow blending (a second set of coordinates is required so I can do this anywhere on the model). This was my understanding how a basic lightmapped model would be displayed - perhaps I'm wrong?
Basically I want to do a very simply example of light/shadow. I thought I could use one set of vertices for one texture (using VertexTextureCoords) and a second set of vertices for light/shadow blending (a second set of coordinates is required so I can do this anywhere on the model). This was my understanding how a basic lightmapped model would be displayed - perhaps I'm wrong?