Marcus,
I see Kendrick have these heaters for RC primary mirrors:
http://www.kendrickastro.com/astro/RCoptics.html
I had one on my 10" Newt but found the Kendrick controller was switching it to control the temperature (I assume it was full on/off with the duty being controlled by the amount of time it was on). This was causing the focus to shift so I've stopped using it. I wonder if your scope control system has a smarter way of controlling the heater duty (perhaps varying the voltage?) so it doesn't cause problems?
Peter