A very straight forward mission that can be completed in about an hour.
Kasumi's mission starts in the Citadel.
Talk to her, accept her in your crew and once you've reached the right planet, you'll be at a party. Yay.
Time to find some DNA, a voice sample and the password to use it.
Kasumi is basically telling you what to do every minute, so you won't get lost.
Once you have everything, go back to the vault entrance.
After the cutscene, take some time to look around because some of the art pieces are very funny ^^
Don't forget to pick up the new SMG and then grab the device you were looking for.
Now it's time for the shooting part, make your way through the basements and once outside, it's boss time !
Lower the ship's shield, and he'll go away letting you deal with some goons.
Repeat several times and Kasumi will finally disable the shield for good.
Destroy the ship, go to your shuttle, watch the final cutscene... Achievement unlocked :-)