After examining the official website, it appears that what you are trying to accomplish isn't actually available. The Ninja Trader platforms supports only the following data streams (as mentioned on their website): Continuum, Kinetic, Rithmic.
I recommend you check with them for any other 3rd party stream that you want to add into their trading platform. Click on the Contact Platform on their website (accessible via the link below) in order to reach them.
Official website: http://www.ninjatraderbrokerage.com/trading_platform/data_providers