I'm an expert when it comes to export from 3dmax to mdl formats.
The exporting is made this way:
*first, only ONE bitmap per model, max of 2048x2048.
*second, UVW the model to fit map coordinates accordingly: if you're using two maps and doesn't want backed shadows, edit the coordinates with the reference uvw generated from the render-to-texture tool until they fit only a designated portion of the map (you decide wich one), and bake the texture - repeat to all elements that goes to the final map. After that, add a normal uvw map unwrapper and LOAD the texture coordinates you saved with the render-to-texture tool. With this, open all the baked textures in a paint program, join them together and make the unique texture for the upcoming model.
Make sure everthing is using the same texture and the same bitmap before exporting.
*third, the exit format from 3d max (if you're not using the max2mdl plugin that works up to version 5.0) is an export to simple .3ds format. When asked if you wan to keep max's texture coordinates, answer YES.
* Open the .3ds inside MED using importing tools.
Done! I strongly recommend you to convert the final texture to DDS format; is incredible compact and fast in the engine.