I'm with PD, let's see it. Even if you run premix you don't have to remove the pump. Just plug it off and leave it. I'll get a picture of mine later. 1) I just run the inlet hose (coming from the pump) into the outlet hose(coming off resevoir), and then 2) have the injector piece you're missing plugged off (I just cut a piece of the hose already on it and ran a screw into it. It's been fine).
Some people use the rubber expansion plugs, but I've had the damned things pop out (you can't tightened them too much) and so have other people.