When I was just having dinner, I realized a important thing. the ST_M_Child.ltb, which is a child model. It only houses some animations for models. If you just import the child model into the game without a main model which has mesh and skeletons, the model will not show up in game.
I don't know if it's because of the conversion. You can try to use the original model in the same way to test it.
The Model_Unpacker not only supports CF but also CA, so I'd be happy to solve your problem.
All roads lead to Rome. I have already got the ST_M_Child.ltb from my friend, Tupac. But there are three models whih the same name. The file sizes are 6.39 MB, 17.2 MB, and 14.5 MB, respectively. Which one do you mean?