What am I doing wrong? X-E1, E2 & Pro1 hot shoe's are not triggering a Yongnuo RF-603C II. A flash mounted on second 603 will fire when the manual (test) button on the camera 603 is pressed, so I conclude the Yongnuo's are working properly, but that the camera 603 isn't receiving a trigger signal from the camera. Cameras set to S mode (single shot) and silent mode is off. Tried in both auto and manual. I've read that X bodies WILL trigger the Yongnuo so I'm puzzled. Thanks for any suggestions.