Finally I got sys-netcheat to work with ReiNX, for those who want to know:
Download the sys-netcheat.kip and put it in ReiNX/sysmodules/
Download the latest Hekate.
In the hekate_ipl file(root of SD), add the following lines:
[ReiNX]
kip1=ReiNX/sysmodules/loader.kip
kip1=ReiNX/sysmodules/sm.kip...