Manbeer, I don't know whether or not you ever added something to activate the center diff lock, but if not and you're still interested here are links to a very inexpensive albeit ghetto/redneck solution.

The first is the original write-up now in the discoweb.org archives (click on CDL Lever Disco2 in the left menu) and the second is an enthusiasts take on the same thing.

https://discoweb.org/oldsite/

Greg Davis CDL Linkage - Erik Burrows.com

And where are you with the Three Amigos?