First of all, the 40d hack always was just a proof of concept (by dataghost), there is no actual hack to obtain or use. on a second note, even if we would have control over the 40d like we have over the powershots, i highly doubt your idea would ever work. the first canon camera that can trigger external flashes without an additional flash unit (or controller) is the canon 7D. it would be very difficult emulating the code without having it
