X10 off-camera TTL flash cord?
I tried the EF-20 with canon flash cord and it seems to work fine, the shot of my wife's bag is in A mode with Off camera flash bounced on the ceiling. I have attached a snapshot of the setup (captured with my GXR).
I am not an expert in flash or any photography, with EF-20 I usually shoot in the A mode with flash bounced on the ceiling, I set the aperture and camera calculates the shutter speed. I believe this is ttl-metering.