I hear you guys talking and what your saying is fine for a experienced gun maker who knows where to properly drill the trigger pin hole but I get the impression that we are talking to a person who isn't an experienced gun maker and he doesn't know where the hole should be.
If he screws up and drills the trigger pin hole in the wrong place he will either have the choice of living with the error (and the terrible trigger pull that goes along with it) or he will end up drilling several holes thru his stock and trigger until he gets it right. Talk about messing up a nice gun!
I still say that using the existing trigger or modifying it so that it isn't as long (easily done with a hack saw), is the best approach for this build.
As was mentioned, that front gate on the casting that is ahead of the trigger can be removed to clear the trigger plate, or the trigger plate can be shortened to miss it. Either of these would work just fine.
As for the rear of the plate, that can be easily shortened to miss the trigger guards gate.
The important thing for WildatHeart to know is that after the lock is installed into the stock, he should carefully mark the location of the sears arm on the side of the stock.
Then position the trigger plate so that the pivot point (the pin) is about 5/16 to 3/8 of an inch ahead of the sear arm mark he made on the stock.
After doing this, he can see how much of the trigger plate needs to be removed to clear the trigger guards cast gates (which will be used to provide material for the pins that will hold the trigger guard to the stock) to pass thru.
If he locates the trigger pivot as I described the guns trigger pull should be just about as good as a simple trigger can be.