I have a 1992 300ce with European Depo headlights. I want to install an HID kit, but I don't see how its possible. Since the HID requires positive and negative, where would I acquire both positive and negative from the one wire that feeds the current headlights. I might be wrong, I did a little reading, but I am still unclear on how they install.

http://cgi.ebay.com/ebaymotors/PILOT-H4-HI-LOW-8000K-XENON-HID-CONVERSION-KIT-HELLA_W0QQcmdZViewItemQQcategoryZ36476QQihZ015QQitemZ250140321688QQrdZ1QQsspagenameZWDVW

Any input would be much appreciated.