Open the door and pull the latch up into the closed position and then pull it even farther ( as far as it will go and then hold it in this position). Take a small nail or paper clip and insert it in the small slot ( located at about the 3 O' Clock Position ) in the back of the cylinder casing. There will be 3 or 4 spring loaded small metal keys (don't know the correct name for them) that you will need to depress one at a time while pulling on the outer chrome bezel. As you get by one another will catch and you will need to depress it to get by it. Remember, while doing this you must be holding (or wire it) the latching arm all the way up as far as it goes. As you get by the last key? the cylinder will pull all the way out. Then you can unscrew the threaded part that holds the casing to the door. The two parts unscrew and seperate from the door.
Check out these pictures on how to remove it.