Suddeth13 is totally right about the difference in light sources moving the focal point from the filament and distorting the cut off. (See
http://en.wikipedia.org/wiki/Headlamp#Retrofitment I usually don't point people to Wikipedia, but this article agrees with me and has its sources in line)
I am not so sure about the use of fresnel lenses since all 'Projector beam' headlights I have taken apart use an ellipsoidal reflector and a condenser (plano-convex) lens (hence the bubble look of the headlight vs the old school flat sealed beam lamps) with a shade near the image plane to form the cut off (Similar to how we use internal shutters on stage to shape ERS Beams). Modern headlamps are specifically designed to work with light originating from a specific point (the filament @ the focal point) which is in a different position and usually a different orientation on a Metal-halide Arc Lamp (referred to as Xenon or HID Lamps). Since the source of light is no longer at the focal point, the image plane moves and the cut off shade is rendered useless (causing bleed, etc... as rmac pointed out).
The only options you have
to avoid the pissing off oncoming traffic or getting pulled over are
1.) Follow njaremka's direction and repoint the headlights (this is what some time ago since both of the above have happened to me in my retrofitted car)
2.) Look into Halogen bulbs which are closer to white and still have the proper filament placement so that the cut off works. -Sylvania makes the SilverStar zXe and Hella also has some reliable Halogen lamps which are closer to the 5000K or 6000K you are looking for.
Good luck,
David
P.S. Sorry for the excessive use of () and ...