I am trying to use the Keltner Channel indicator from here:

Keltner Channel - MQL4 Code Base

It is the only Keltner Channel indicator I have found for MT4. There is a variable to modify the period used for the middle line, but there doesn't appear to be one to modify the upper and lower lines (multiplier constant lines). I can't even see what it is currently set at. I would like to be able to change this to my own setting. Does anyone have experience with this or know how to modify the indicator to allow custom settings for the multiplier constant?