I just bought a Canon EOS Digital Rebel XTi camera and I have a Quantaray QB-6500A flash unit left over from my EOS Rebel XS film camera days. The flash has a "CN AF" module on it, which is only TTL compatible, not E-TTL, and the XTi won't fire the flash. Is there a module available to make this flash unit work with Type A (E-TTL) Canon EOS digital cameras, or should I just buy a Canon Speedlite?