OK I think this is something to discuss in another topic BUT, THIS WILL BE an easy answer.
Getting the orange ( Canadian ) box will save this, but this involves try to get the right part, maybe not that easy... maybe yes. Easier if you have an acces to Canadian buddy close to a Canadian JY.
The next solution is TURN AROUND the two yellow wires arriving to bulkhead, or jumping the two wires arriving to interlock control box, or find the two yellow wires into the engine harness and jump them. You choose.
This is how it is wired the starter relay wiring and interlock system:
I made this diagram long time ago. Canadian boxes got these two wires internally jumped into the box, on printed circuit box itself ( just right where I draw the arrow )
this topic has being already discussed around here using this same diagram, same as dodgecharger.com and Moparts.
NOTE: allong with this, need to make to work the NSS system too, because if not you'll be doing nothing, and still will need to use tricks to start it.
NOTE 2: The Interlock system also used the NSS system to give you the seatbelt warning signals when gearing ( if you care ), but not really to allow or not the starting procedure, just for that.