u have to take the air cleaner off to see it......see the metal tube that the short hose u have marked, coming out of the heater, goes into ? on the other end of that tube, there is a hose, which connects it to the water pump housing (at the return) look under the air cleaner.... this is where u want to put your T fitting for the water return....i will make pictures of my new setup later and post them so u get an idea.....keep in mind, its not "neat" (all perfect like it looks like it came that way from the factory), but it is all very heavy duty, and does its job !
(im talking about my setup i put together on the cheap and assembled in an hour)