You create a new shipstyle in-game by customising an opponent (it will let you create new shipstyle using any templates that are kicking around).
If those ships work in TOA, you need to copy the files inside of 'Hull' to My Documents\My Games\GC2TwilightArnor\ships.
However, those will only work for the particular race they were created for (Terrans).
I checked it out and had no trouble getting them to work with Twilight.