TIG,
Using Sketchuv plugin for uv mapping there is a need to triangulate faces (right click and choose 'triangulate' option in sketchuv) prior to using your exporter. Otherwise texture will be splitted into as many textures as there are faces. And this is only the case when we are using 'tube map' or 'quad face map'.
This video tells all the story.
http://www.youtube.com/watch?v=baQwxL6mgMQ