I'll give this a go...
Step 1 - Create a new ability to deploy the new starbase (excerpt from AbilityDeployStarBaseTech.entity):
Step 2 - Create the new StarBase entity of course (self-explanatory)
Step 3 - Add your new Death Star to the proper player entity (excerpt from PlayerTech.entity):
I'll let you know if it works... I am definitely not a moddeler however... can't help ya there.