Animated/growing projectile

I want to make an animated/growing projectile, how do I do this?
I have already set up the weapon and projectile in a script.
This is how it works so far.
I have a slow moving projectile:

muzzleVelocity = 30;

with a short lifetime:

lifetime = 1000;

and a very fast firing rate:

stateTimeoutValue[3] = 0.01;

And all this is emitting lights as it goes.

All this gives me a massive firing power with a range of 30 meter where the projectiles dies out.
I have real nice particle setup for this.

What I need is the projectile.dts to grow bigger as it moves slowly forward until it dies out 1 sec and 30 meters later.

How can I get the projectile.dts to grow?

Should I animated it or can I scale it in the script?
If I would anumated it how can I activated the animation when firing?

Ohh, in case anyone is wondering what strange kind of weapon this is, let me shed some light on that.
Its a flamethrower :)

Anyone got any ideas on this?

// Clocks out.