Alpha testing doesn´t allow semi transparency, and that is what you want. Ao Superkus first post won´t help you. The only fix would be a model without faces on the backside facing the cam. Alternatively you could sort the faces, but that means quite a lot of work and is really slow with many polygons.

Superku,
While the code is no shader code, the graphics driver will make it a shader as otherwize modern hardware wouldn´t be able to draw it. As there is no fixed function pipeline anymore for a couple of years, only shaders .