94 Headlight Adjustment?

I feel sort of stupid for asking this question, but I'm having a hard time figuring out how to adjust the headlights on my 94 LeSabre.

I found the two black plastic torx/star fittings that seem to be the vertical and horizontal adjustments, and I have the tools to fit them, but they don't seem to want to move. I was afraid of breaking one by twisting it too hard. Are they locked in place somehow, or might these simply be frozen from not having been moved in a long time?

Thanks,
David