Merchant Dock Build Options

'Ello everyone!

A friend and I are working on a mod, and we're trying to find a way to add a few other custom ships to the Pirate Merchant Dock that you can capture in most space maps.

So far, we've found the N_Orbital_Construction_Pod in SpaceBuildablesSkirmish, but if we add anything to it, the additions never show up in game.

Can someone here who has any experience with this explain how we could go about doing this?

Thanks.