Odd - just received a brand new asym from UK Halsey last week (Matrix Flasher) and it did come with a tacker sleave. Their setup is similar to the graphic Hard submitted however they recommend trying to ensure the tack line block is out in front of the headsail/furler to ensure best setting. I haven't set it up yet - just going by what was shipped and their setup dvd...
Let us know what you learn after setting it up. I find it odd that they would be encouraging you to secure the tack along the headstay. In my experience, the goal is to fly an asym as far forward of the mainsail as possible, where it gets the best air.
The best way to achieve that is to fly the asym chute from a sprit or spin pole (set-up like a sprit). Take a look at all the sport boats (Melges, J-boats, etc) with retractable sprits that fly asym chutes. They put the tack way out in front of the boat at the end of the sprit, where it is not secured to anything other than the adjustable tack line.
Many cruising boats lack a sprit or sprit-pole arrangement, but the next best thing is to let the tack float out in front of the boat as far as possible. Securing it to the headstay, which angles aft from the bow, seems counterproductive. It would also make inside jibing much trickier.
Then again, maybe the cut of your UK sail is more for reaching than deep reaching like many of the early asym sails. But I still don't think Hardwork needs anything more to fly his chute -- the absence of any tacker/parrel arrangement suggests to me that the previous owner flew the sail just fine without it.