I've just come back from a party and I am absolutely hammered atm (i.e. for all you non-Brits that expression means I am very drunk), so can't think very clearly right now. But a provisional solution to this is to say that to do what you want has absolutely nothing to do with the weapon file settings. The trail of smoke and fire you see as you launch the rocket is handled by an .EFX file. You quoted flare_artillery_runner.efx as the .EFX used by the rocket launcher weapon file you are using. That file runs an .EFX file named fx/misc/flare_artillery_marker.efx. All you need to do is add the explosion FX code to the very bottom of flare_artillery_marker.efx. Then, when flare_artillery_marker.efx runs, the very last FX tp occur in sequence will be the explosion FX code.I do not understand what else needs to be edited in weapon file. I have only smoke at the end
If you are unsure how to do this, please attach your explosion .EFX file to your next post. I will download it, and add it to the foot of flare_artillery_marker.efx.