Having trouble with a Pentax *ist D (in wireless flash mode, on board flash popped up - used as a controller only) trying to trigger 2 - AF360FGZ wireless flashes (set as slaves - in the P-TTL mode) into white umbrellas. Settings have been triple checked - and flashes will fire (wireless) when they are pointing directly at subjects. When they are pointing into the umbrellas (sensor is away from subjects) it seems that there is not enough light reflecting off of the umbrellas, from the control flash, to get them to fire. I was under the impression that the flashes would work with wireless communication and not by "optical" means. Called Pentax and they will look into the problem - not holding my breath for a response. If someone has had experience with this flash and the *ist D and could help me out I would appreciate it. Bruce N.