Well the issue there is that the wrist twist is actually a small part of what makes the technique work. The real trick is to get your uke in a position where you can settle your weight over a point where they can be unbalanced. The "lock" really just serves as a mechanism to maintain connection with uke's centre.
I think this picture illustrates my point:
That's an awesome picture! Thanks for that.
It definitely unbalanced him when I applied it but it was difficult to get him to go to the ground with it. I see what you're saying, but it feels so unnatural when I couldn't get that bend that I'm used to. I'll keep practicing!