In case someone is having trouble with plunder, steps to sucess (realism, but should work for any other difficulty I would asume)
Target the top beam on the siren
- c114 (gamma 1 destroy subsystem)
Form up right behind beta wing, target Elisa's left main beam (middle cruiser), stay below the cruisers nose and aproach directly from the front where the turret coverage is minimal. As soon as you have range to drop paveways launch 2 of them at this beam, target the right beam and when you are at about 700-500 metters (about to collide) launch your other 2 paveways and kill this beam.
Immediately turn back towards the indus and dodge incoming turret fire and 0 to 2 perseus which are now chasing you. Let the corvettes kill them.
Around this time you'll see the directive to kill the siren's beams complete. C-3-9 to order gamma to attack anything, press E and C-3-6 (ignore ship) to tell them to ignore the cruisers and siren.
Lean back on your chair and about 4:30 minutes into the mission go towards the Agincourt, sit on his ass and launch your 2 remaining paveways. Move away from turret range and resume leaning on your chair until the end of the mission where the pods escape.
To battuta's comment about slowing the UEF ships, That might help, but the main issue is that right now the cruisers are hardly ever in the gauss cannon cone of fire. Sit back and count how many times the frigates actually fire, it sure ain't much.
Another thing I noticed once I sat back and watched everything that is going on is that once there's no fighters left, alpha wing just sits there and won't even try to fire at the cruisers or siren.