also remeber, that when you have extra faces ( like the one's you deleted on the edges) make sure to merge the vertices that are left behind. If you bring up your poly count disply and draw a marquie around one of the vertices along the edge that you deleted the extra face you will find that there are really 2 not 1 and this will cause you some problems. If you still don't get what your after with extruding your faces, after you have set keep faces together, try clicking the round center botton on the extrude tool.