Marc,
Let me know when is a good time for you next week(except Wednesday) and I will come out with my meter as well as a few tools and LED's etc. and see what we can set up (as long as you supply the beer). It may be a simple add-on or it may need something like a relay that is tripped when the element turns on. I won't know until I can get inside it.
Personally I wouldn't wire anything inline as it could/will have an effect on the current draw of the circuit. If it takes it beyond it's design spec's or changes the load in a bad way it can have some repercussions you don't want.
Cheers
Darren