Neuromuscular Stimulation

Hello guys,
This is my first day using this amazing forum and the first time i am using the iPad app.
I had a lot of questions but i have been reading a lot and could figure almost everything out. However, one question still remains...
Apart from working out at the gym, i also use a neuromuscular stimulation device to work my abs, pecs and other muscles. It works really well and the results are great. The question is... i tried to add that kind of exercise on the "Strength" exercises on the iPad app but, obviously, it doesn't appear on the list... Is there a way to add it? If i can add it manually, how do i know how many cals it burns etc etc?
I know it is a hard question ... but i only bother you with this because i couldn't find the answer even after looking all over the web.
Thx for reading and for the patience.
Hugs