These are set in each of the weapon's object lua files. Example below from the D18 pistol. So to change it to a profession I believe it would be a pretty deep re-write but should be do-able.
-- See http://www.ocdsoft.com/files/defense.xls
defenderDefenseModifiers = { "ranged_defense" },
-- Leave as "dodge" for now, may have additions later
defenderSecondaryDefenseModifiers = { "dodge" },