Light up your firework?You can only shoot them in the air with the dispenser.
You have to craft a firework star to make the explosion more colorful etc.
Why don't you use Google? Here is the result if you would: http://www.minecraftwiki.net/wiki/Firework_Star
I have the same issue. I downloaded the snapshot and went to creative to test it out and I cant craft any of the fireworkstar recipes and when I launch my fireworks the dont do anything. Plus what I think what he means by light it is to launch it or what ever.