Can either do it by joining the lines to a T piece, running a small smount of fluid in a resevoir off this, although I saw this as not a TRUE manual rack as you're still pushing fluid about
Instead I stripped the rack and removed the seal from the rack shaft that seals the space between the inlet/return PS lines, this seal usually pushes the fluid back and forth through the pump loop
Without the seal you have more of a TRUE manual rack. made sure to relubricate everything accordingly when reassembling, just need to adjust the rack tension to honda specs as per manual, fit my new inner track rods and it's good to go back onto the subframe