Accessing Parent data in datablock function

I may have a fundamental misunderstaning of this but this is the best way I can explain it for what I know.

I am trying to add radial damage to my weapons. I have a tank that fires numerous types of ammo and each do differing damage at differing radii. I have been modifying examples and tutorials to get what I want so I am left here missing some part without a complete understanding of the code I am using.

The datablock looks like this:

datablock ProjectileData(TankPrimaryProjectile)
{
   explosion           = TankPrimaryExplosion;
   waterExplosion      = TankPrimaryWaterExplosion;
   splash              = TankPrimarySplash;
   velInheritFactor    = 0.3;
   armingDelay         = 0;
   lifetime            = 5000;
   fadeDelay           = 5000;
   bounceElasticity    = 0;
   bounceFriction      = 0;
   isBallistic         = true;
   gravityMod = 0.80;
   hasLight    = true;
   lightRadius = 4;
   lightColor  = "0.5 0.5 0.25";
   hasWaterLight     = true;
   waterLightColor   = "0 0.5 0.5";

The ammo object contructor looks like this:

%p = new (Projectile)() {
      dataBlock        = TankPrimaryProjectile;
      initialVelocity  = %muzzleVelocity;
      initialPosition  = %obj.getMuzzlePoint(%slot);
      sourceObject     = %obj;
...snip...
      directDamage     = %damage;
      damageRadius     = %radius;
      radiusDamage     = %radiusDamage;
      radiusType       = %radiusType;
      damageType       = %damageType;
      impulse          = %impulse;

The function that is giving me trouble is:

function TankPrimaryProjectile::onCollision(%this,%obj,%col,%fade,%pos,%normal)
{
   // Apply damage to the object all shape base objects
   if (%col.getType() & $TypeMasks::ShapeBaseObjectType)
      %col.damage(%obj,%pos,%this.directDamage,"TankPrimaryProjectile");

   // Radius damage is a support scripts defined in radiusDamage.cs
   // Push the contact point away from the contact surface slightly
   // along the contact normal to derive the explosion center. -dbs
   radiusDamage
     (%obj, VectorAdd(%pos, VectorScale(%normal, 0.01)),
      %this.damageRadius,%this.radiusDamage,%this.radiusType,%this.impulse);
}

Is my assumption correct that the function onCollision is based on the TankPrimaryProjectile datablock "namespace" (I know that there really is no classic namespace in Torque script)? If so then I know why %this.damageRadius,%this.radiusDamage,%this.radiusType,%this.impulse have no value because those are defined in the Projectile object that I create.

If this is the case, is there a way to retrieve these values in TankPrimaryProjectile::onCollision?

I am hoping to not have to set up a new datablock and possibly a new onCollision function for every one of my ammo types.