First you need to make a material.
http://www.feral-heart.com/index.php?option=com_jfusion&Itemid=2&jfile=index.php&topic=44951.0 (http://www.feral-heart.com/index.php?option=com_jfusion&Itemid=2&jfile=index.php&topic=44951.0)
And then you use either ceiling.mesh or basicCube.mesh.
If that doesn't work I can try to texture it for you. :3