Problem with drawing substitution after importing swf from flash

After I import the swf file into Toon Boom Harmony, everything seems fine at first, I got head for a layer, arm for a layer, body for a layer, etc
However, when I start to animate the character, and I want to make some new drawings in the drawing substitution.
I found that “Every layer shares the same drawing substitution!”

That is, when I add a closed eye drawing (ex: the 10th drawing in the drawing substitution) in the eye layer,
than it also appears in the 10th drawing in the drawing substitution of the arm layer.

Is it possible that every single layer have their own drawing substitution? So I can make everything tidy a little bit

You would need to import each body part (layer) separately.