Have to revive this one, since, upon a recent review, there may be an existing rule that potentially contradicts this ruling (certainly in spirit if not necessarily in word). Per AToW p. 211, if a vehicular weapon that damages the last point of meat deals its converts the damage to the attacker as if the trooper were conventional infantry. This creates awkward situations where Elementals can easily survive finishing blows from SRMs and AC/2s, but instantly crumble when finished off by a lucky burst-fire from an auto-rifle.
After some thought, the ruling also conflicts with the given TW-scale rules for BA troopers with Dermal Armor (IO:AE p. 74) and Dead vs. Truly Dead (CO p. 198).
Proposed alternative solution: Each hit to the last point of meat deals 6 BD. This matches the vehicular weapon conversion, hits the 6 BD threshold as a kill when converting between AToW/TW, and as a bonus gives a nice, clean 50% damage increase over an AToWC Operator Hit critical effect.