Buy Catapult missiles if you can. On the target status menu, click on the 'Switch to Target (sec 4 pg 28). This bring up a picture and some info. Click on the icons to the right. They cycle through the sub targets. Target one of the missle points and destroy them. Make sure you are pointed directly at the target. Keep firing missiles and switch to guns every once in a while. Used up a bunch of shield batteries but managed to kick butt.

The obvious problem is that you're using a truly crappy ship.
Cavalier won't cut it.
Buy something better.

like a barracuda (u can get it almost anywhere in kusari) dat is what i used w/

2 adv. skyrails
2 lavablade mk3


its really overkill but if u want u can buy sunslayer torps also avalable in kusari

What trade routes did you guys run in the Kusari system after that mission to get money?

You probably should have upgraded your ship long ago... I did a couple of freelance missions in Bretonia using the Cavalier, then quickly switched to the Crusader, which I kept until hitting Kusari. There I bought the Drake after some time (that fighter has an amazing turning speed), and then went for the Barracuda (the BountyHunter HF). Using AFAIK the standard Shield Generator and some average weapons for the stage of the game I was in, Mission 8 posed no problems for me. Actually I think it may have been one of the easiest in the game for me. I suggest you earn some mroe money and get a good ship, especially since you won't do that much more Freelancing after Mission 8, and will need some money to buy eg Shield Batteries, Nanabots, etc. A Torp Launcher is quite handy (big understatement) for the last missions as well... (torps will also maul weapon platforms, in case they would still pose a problem)