I just purchased an umbrella, stand and bracket to hold my flash. I understand how this will work in TTL with my SB800 but have a question when I add an SB80 to the mix. The SB800 will be the master, the SB80 the remote and with this combo on a D2H it is my understanding that you have to set the SB800 in AA and the SB80 will trigger with SU-4 wireless. When you do this it would seem that with the SB800 pointing into the umbrella the flash sensor would not measure the light from the subject; ergo, would not shut off at the proper time. This in turn would cause the SB80 to follow the lead of the SB800. Am I wrong? Must I use the flashes in Manual? Any advise would be appreciated.