wow! fave ko 'to... puede ba malaman ang exif nito? he he he 
Hey Bro no prob.... kwento ko na lang yakang yaka mo yan. Sa Digital Camera walang double exposure pero you can achieve almost the same effect sa "bulb setting" long exposure in a count of seconds depende sa presence of light at camera setting mo, considering the aperture, speed and the ISO. (gamit ka lang black cardboard) For example first count 5 secs in bulb setting tapos takpan mo ng black cardboard yung dulo ng lense mo, wait ka tumigil yung ferriz wheel saka capture mo ulit in 3 secs.... sabay sara ng shutter mo. done! (be sure yung takip mo no light coming in at dapat naka cable release ka para walang galaw)
I mean it would always depends sa sitwasyon ng subject.... you can start experiment same sa fireworks long multi-exposure kahit hanggang tatlo o apat "takip - bukas - takip lang with counts depende sa anong kulay at liwanag nung fireworks. You will be amaze sa results then you adjust what is needed. Cheers!