Combat and bombing planet

[thecyclemania]

During one of my recent game, I was involved in a battle (against the AI) where my fleet is attacking another fleet and some weapon platforms on a planet.

After a couple of turns where I manually controlled my fleet, I decided to let the computer do the rest of the battle.
So I turn the "auto" option on.
So the only thing I had to do was to click "end turn". After 10 minutes, I was really bored so I decided to toggle "auto run until the end of battle" (or something similar). Basically the computer was controlling my fleet until the end of the battle, and I can only watch.
Watch I did, but to my horror, after the WP were destroyed, my ships continued to fire on the planet until all population and structure were annihilated.
Is there an option in auto-combat (or even strategic combat) to turn on so your fleet won't destroy the colony, just the defenses.

This could be usefull, since my troop transports are within range to invade the planet after all the defenses are gone...

Thanks for any help

- thecyclemania