If you can get hold of it, the original NA rulebook had a design system in it. Given that each weapon in original NA is 1 weapon system/dice in ACTA:NA, and the points are very similiar this might be one way to 'port the ships across. A certain amount of comparison between existing ships would be required for the turns and speed, however. Damage points and thresholds have a definite link between the 2 systems (can't remember exactly how much it is - but it's easy to work out) - so they could be easily done. NA ships (of both systems) have precise rules on how many and what size of turrets and weapons may be fitted in place on the size of ships, so these would remain the same.