headlight replacement:

1. take off black rubber covering cap
2. unplug wiring connector from bulb (just pull connector body, NOT the wires!)
3. There is a metal "bail" that fits over the bulb into a metal tab. Unhook and rotate out of the way.
4. bulb is free, probably will fall part way out of socket.
5. stick new bulb in, making sure NOT TO TOUCH THE GLASS of the new bulb. You will have to rotate the bulb to get the H7 tab in the correct orientation (down I think).
6. snap the "bail" back over the bulb, plug in the wiring again, put the rubber cap back on.

One thing you might wat to do before is park in front of a wall (5-6 feet away) or something with the headlights on and trace the top edge of the light pattern with a pencil. Then do your bulb swap and verify once complete that your aim is still good. If you didn't seat the tab properly you'll see it on the wall immediately.

Another note: several of us have had 1 or both H7ST's in a 2-pack turn out bad. I think Phillips musta had a bad run or something. But where I bought 'em (Wal-Mart) no questions asked replaced and the second set worked great. No problems at all with my 9006ST's.