You have 2 lines coming out of the brake proportioning valve going to each of the front wheel brake calipers.
Disconnect both of them and plug off 1 of the two holes in the prop. valve.
Put a new short line going to the line-lock solenoid "in" side from the single remaining unblocked prop valve fitting.
Put a "tee" fitting on the "out" side of the line- lock solenoid.
Reconnect each of the hard lines going to the front calipers into the "tee" fitting on the "out" side of the line-lock.
Bleed the front brakes, hook up the electrical part of the line-lock and you are done.
I've always put an arming switch on the line-lock for added safety. You can plumb the system using parts store fittings and hard lines to get your solenoid put where you want it. It's a PITA but the results are COOL!