Hi! Can you tell me if I can still use AF-assist in my SB-910 when attached to a Cactus V6 on top of my camera? The AF-assist works when the flash is attached DIRECTLY to my camera, but doesn't appear to work when I put the Cactus V6 on my camera's hotshot and then place the SB-910 on top of the Cactus V6. What am I doing wrong? I want my on-camera flash (atop the Cactus V6) to remain in FULL MANUAL MODE. I don't want to use TTL for my on-caMera flash, but I would like to use my AF-assist (the infrared) to help me focus in low light situations. I have a total of 5 Cactus V6 units - I want the on-camera flash (the one that sits on top of the V6 on my camera) to be in MANUAL mode (not TTL); the remaining 4 flash/V6 units are off camera on stands. Thank you!