To modify the RWN322p TWT PSU, it is handy to have the schematics. Here you can download the
different parts and put the total together again. Print it on A3 is best.
To disable the Helix-tripout function you need to bridge this electronics inside the RWN322p PSU. The position were to do is in the picture to the left. It is close to the output plug on the PSU, that is just visible at the right edge on the picture. The solderstrap is connectin the two larger positions, see also the zoomed image below this one.
Detail of the solderstrap.