How to do multi-pass rendering

I’m making an outline effect by the method of back-face fattening, which requires a additional pass that culls the front face.
I have referred to a couple of tutorials before but they aren’t the thing I’m trying to do. The tutorial Custom Geometry Drawing uses a self-defined vertex buffer instead of scene objects, while HOWTO: Render FPS weapon does render scene objects, but it uses the material of the object instead of a custom shader. What I am doing is to render some mesh objects (with a certain tag) in the scene two times, once in the default way, and the second time with front culling and another custom shader.