I have recently purchased an E-PL1 and notice that it has manual flash modes (i.e. no pre-flash). I believe this means I can trigger my Canon 580ex II speedlite as an off-camera optical slave (the 580ex II has optical slave capability that triggers when another flash is detected). The same probably works for the Canon 430ex. I'm going to try it out, but has anyone else tried this? If so, any tips?