Yes, I used the most forward hole, not the one that is normally used with TriRig shouldered cable stop. The hole is large enough for a cable. I didn't want to drill the stem so I made a shoulder on the inside with a stainless collar centered over the hole (see picture) that had an ID that was slightly larger than housing end cap OD to serve as stop. Some 2 part epoxy around outer base and it is solid. I am sure it is not TrigRig approved but I am confident it is fine as material (stem) has not been compromised. Time needs to be taken using good quality cable housing and use of flexible brake noodle or linked housing to enter shoulder perpendicular minimizing lateral forces on collar. I can always go back to housing through primary. BTW the actuation is actually better with this than when I did it with housing to fork mount stop.
An alternative is to discuss with TriRig about using their shouldered stop, but I can't imagine they would bless drilling the stem (or doing what I did for that matter), and I don't fault them for that. Perhaps in future designs they could have several exits for their stop.