[Rollo]

I think dogscoff is right. You have to destroy the weapon platforms first. The troops will stay behind until this is done. Once the WPs are finished the warships stop firing and scatter (actually run for the corners!, pretty silly isn't it?) and the troops move in for the capture. Works really well for me.

About the Kamikaze attack after the warships are dead: I don't know. I have never seen this, but here is what I suspect: The troop ship in a mixed fleet will wait until the defenses are finished (that I know for sure), BUT if there are no warships it tries to capture the planet anyway (that is what I assume). If this true, you might turn it to your advantage. Try to capture a planet with troop ships only. Use two or three of them and shield them. Hopefully one gets through to capture the planet even with WPs intact. Might be worth a try (if you try this and it works, let me know). It might also be a good idea to put some point-defense on the troop ships to kill the sats, because they will fire on the planet after the capture. In one of my tests with an AI that captures planets, a planet was glassed only moments after the capture by the sats that were still in orbit.
I hope I could be of some help.

Rollo