I got three soft boxes that are slave flashes, I got a remote flash I slide on my camera flash shoe and I plug the other recieving end of the remote (the trigger) one in the the back of one of the flashes. When I take a photo on AUTO they all go off like usual, but when I put the camera on manual or AV and adjust my settings the way they have been all summer long in my garage. THE FLASH WONT FLASH! It wont flash with my remote or my 580 EX. What little mistake did I make or what did I do wrong?