Making the player ride a firework (Skript help)

[ReaMart]

launch ball large coloured yellow, red and orange fading to light grey and black at arg-1's location with duration 2
make the player ride a firework

I have the above in my script, but this makes two diffrent fireworks:

1. the one with the fancy colors, by the first line

2. a normal firework on which the player is riding

I want the player to ride the fancy firework instead of a new one.