P-watch

[Trolkar]

Have anyone installed a p-watch? – It is almost impossible to reach the parking disc from the driver seat. Therefore, I have bought an electronic parking disc. P-watch. – Has anyone tried to install a parking disc.
It needs +12 v and ground, but I also needs to detect the ignition signal. (A drop in voltage of minimum 0,1V) – Where do I find the correct wire?

http://www.p-watch.com/Produkter-/-Webshop/P-Watch---Produktvisning.aspx?ProductID=PROD3