You could use cube-mapping. I suppose that's what you doing above. Basically cube mapping is one texture with six frames in it. so createtexture (768,128) and don't forget to put the cube mapping flag in. Your probably better create 6 quads and texturing each of them, and arranging them in a box shape. OR, create a texture with all six sides on it, and manually adjust the uv co-ords of each vertex so that the texture fits correctly.
Or, and final or, Create your cube in a modelling program, and uv map it yourself, saving alot of cding :D
Or, and final or, Create your cube in a modelling program, and uv map it yourself, saving alot of cding :D