Sorry about the delay, somehow I missed your reply... :lol:
Anyway, it does look like you've found the correct points to monitor. But I wouldn't even think of trying to hook this to your Homevision without using some kind of isolation - that panel looks far too nice to risk taking it out with an errant surge (which are pretty common in a HVAC setup)!
That said, what are you comfortable building, and what stuff do you have available? The easiest method would be to use a 24VAC relay, but if you don't already have one they can be harder to find and a bit pricey to boot (at least when looking at a $10 mark).
An opto-based circuit would be my favorite. Easy enough for anybody with basic soldering skills to build, but for price it again depends on what you have available. The parts themselves are under $10, but if you've got to order the stuff, you bump into minimum order fees.
Anyway, the hard part is done. Let's get it talking to your panel!
Jerry