Spring RTS Engine

Trying to do some fancy stuff with explosions. Wrote the following code in a Gadget's synced loop:

function gadget:Explosion(weaponID, px, py, pz, ownerID)
Spring.Echo(weaponID, px, py, pz, ownerID)
end

...and it returned nothing. It's like the function isn't even being called. Any idea what I might be doing wrong?

Script.SetWatchWeapon(number weaponDefID, boolean state)

Not to be more obtuse than usual, but where do I invoke that? Within the Explosion loop, or do I need to use COB-->Lua and set it up when the Unit's created, or is prepping to fire? I take it that watching a weapon must be expensive?

Nevermind, I've got it. I'll post up some code here in a bit, I've gotten an idea about how to do some interesting stuff.

[EDIT]

Forget "interesting". This may completely change how we do effects with this engine.

[/EDIT]

Yeah, we call that LUPS.

<laughs>

Sorry, but no. It's not LUPS. Not even slightly. Much more useful. Screenshots when I've refined the content a bit.