HID Replacement

I have a 2003 Jetta and I bought HID replacement bulbs but when I got to the light housing and removed the boot the stock bulbs have plastic tabs that hold it in its place and I cannot remove them. There has to be an easier way to replace factory bulbs. Please explain I know there are a lot of peeps out there who do this. Thanx for the help

Looking from the front of the car the black circle clip turns clockwise to loosen. Sometimes its really hard to turn if they havent been off in a long time.