How can I add a concrete agitator to my Reed A30HP, to help flow of concrete to the cylinders

Attach a vibrator directly to the hopper instead of on the grate.  Bolted directly above the shift lever on the back side of the hopper. 

Check out a Schwing agitator, they've got a couple paddles towards the middle shaped kinda like a golf club (putter) they sort of pull mud towards the intake.