Once you get onto the Separatist ship, there is a platform you can raise towards the back. Use a jedi's force to get across to the other side, or a droid can also raise a different platform using the panel. Once you get all the way to the right you'll find a bunch of gold bricks on the ground. You need around 30 to build the door. After building the door, get into the elevator and the level will be right there.