Essentially what you need is to activate the relay that turns on the power leg from the battery. So everything will be wired as normal minus the switch. Ground on the relay to ground. Ground on lights to ground. Hot(constant) from battery to relay. Hot from relay to lights. Here is the difference, instead of using the switch you will use the tap of the high beams to activate the coil of the relay instead of the switch on the interior. Very simple install, keeps you from mounting another switch inside. Remember to take the covers off of the lights before turning them on. In a matter of minutes those covers could get really hot and start other problems. Just take your time, be thorough, and remember to use shrink wrap!
Good luck, let me know how you do.