I have a sb800 speedlight which I have hardly used & have this wkend decided to really get to grips with all the options & functions .I think I have bottomed it except for this. How can you set it up for iTTL fill - flash "off camera" .I have googled a website that say ,they do this, but dont indicate how.I am not referring to setting up the commder mode etc , just the fill aspect. Does any one do this or know how regards colin.