I have been unable to complete the Kashyyk mission in the Campaign Mode, yet I seem to win everytime in GC or Instant Play... I get to defending the Refinery, I kill all the snake driods, yet the Refinery still goes (since I am in a turrent what can I do?)

be an engeneer and be a tank. Mobility is your friend

Jawathehutt is right the mobility and extra firepower will give you an edge in the battle. Good Luck to you.

Don't let the tanks in. It's much easier to guard if you continually repair the gate winch - then you're only up against 2 or 3 AI soldiers at any given time, and with an engineer that's easy.

or you can be a heavie and drop mines at the entry and get ammo by from all those who youve killed, but the tanking method is the easiest since the tank respawns in about 10 seconds after youve died

Go rocket trooper first, plant mines around then switch to soldier and get into a tank, after the tank takes some hits, turn to engineer class and repair then turn into a rocket trooper again so you can lay mines down in from of the command post you defend on the beach (turn the infinite ammo cheat for mine slaughter if you want) and blast away the enemy tanks and spider droids, after this turn into a trooper (or Yoda) and clean house, worked for me

be an engeneer and be a tank. Mobility is your friend

yeah, u must use the tanks that are available to u otherwise the enemy tanks will blow the refinery away.

Combine jawathehutt and maveritchell and u have would great strategy.Bottom line....Be and Engineer

Heres how i get past it be engineer then shotgun or get in tank and blast them when the sea walls breached go to the control panel and switch to fusion cutter. repair Keep
Doing this it's how i won.

i use the tank as an engineer
try to tell one of your allies to get in the turret on top

Just be a regular trooper until the wall thing opens, then get in the tank and lay out the law.