I can't remember for sure, you need a DMM -but I seem to remember that if you strip off the small electrical loom off the aerial unit yourself you are left with something plugged into the original loom which looks like:
- top left -yellow is earth, ground your amplified aerial to that
second one on from top right is a red wire that is switched live -check that out with your DMM
connect the regular aerial socket as per normal
...it was as easy as that! Reception is much better than with stock aerial also. I used bodyshop never set putty bead and a small amount of ali plate to seal up my original aerial hole before putting the spat back on. No way water is going to get through there.