I am in your industry. HR is not my enemy. HR can and should be your friend. The days of being a renegade headhunter crashing through walls to wrangle a fee out of your clients has been "over" for quite a while now.
Believe me Chaser - you will have much more success once you can get your mind around a relationship WITH HR rather than against.
If you would like some personal help on how to bite the bullet here and make some friends "over there" then please feel free to call me directly any time. Day or night. I can help.
P.S. I have a client right now with positions in 8 different facilities. I am working WITH HR _and_ the HM in each situation. All of this has grown within my relationship and cooperation with HR - not outside of it. If I was still going around punching HR in the face - I wouldn't have anywhere near this kind of expanded opportunity within just one client.