From my understanding, the z pattern on the real HID housing comes from the parts located in front of the hid bulb called "SHIELD" That shield is basically the same shape of the beam you posted that created the Z pattern. Basically, the left is lower than the right to avoid direct illumination of oncoming traffic. Both left and right headlights have this shield, and when aligned, tech normally adjust the beam to overlap. (basically 2 z pattern that merged or overlap into one.
Your stock housing doesn`t have that perfect Z shape "Shield" that gives a distinct HID pattern. But you still see a z pattern but not like the one you posted above . Also, the beam or angle of beam is not as wide as the real HID projector housing. The only way to get the real Z pattern is to have it send the projector housing for HID retrofit conversation.
http://www.lightwerkz.net/
BTW, if you look at the picture above, you can see 2 z pattern overlapping...
Here is the actual pic of the shield that produces the z pattern.
Below is my ex35 non HID projector w/ hid kit .
Modified by AWGD8 at 7:32 PM 11/4/2009