All what you need is Morgh's editor. When you run it, click on browse and find where is your module. Then you click ok and that will be save. Then click on Factions. When you finish edit one faction click update faction And for all too( finish1. faction than click update, finish 2. faction click update and for all other do same), when you finish updating, click save changes and yes and ok. Start new game and your edited factions and other what you edited will be in game.
http://mountandblade.mircon.de/wp/morghs-mb-wbwfas-editor/morghs-mount-blade-wbwfas-editor-en/ this is link of editor
Enjoy!!