Yes, those Givi instructions suck! The one that got me was the lack of clarity on the connector that goes into the plate - you have to put it in from the TOP, not push it up from underneath! Duh. I also found that if I removed the two rubber stops at the back top of the plate the box sat more firmly and was easier to put on and off. Maybe those rubber stops are preventing the connector from seating properly? Pull them out and try it - you can always push them back in.
Unfortunately I bought the E52-NF which came with the lights already installed, so can't help you on that. HOWEVER, why not try it the other way anyway? Can't hurt and the worst that will happen is it'll not fit properly and you'll have to change it back.