Select ...

Make path ...

any setting between 1.5 and 2.0 will work

File/export

open in AI

outline black fill white

the outer shape gets a black fill ...

inner shapes get white fill no stroke

it will make sense what to do as you go along

you can separate by layers and maybe see something like this on the black fill layer on the bottom

a bunch of white fills

you might need a second black fill layer above the white for details

copy, then paste into flash

ctrl-b once

ctrl b again

delete anchor pts as needed

delete ...

adjust handles with the subselect tool as needed to refine bezier curves

or adjust lines with the direct selection tool

make lines THICK where there would be shadow and THIN where there is light

You will also want to use the ALT key in the subobject select too to change corners to curve anchors and break handles.

gradually your lines will get refined. this will take time.

the refining process can be obsessive. take breaks to look at your work. is the line consistent the way you want? is the line weighted nicely?

shadow areas can be copies of the local area filled with black an made into a symbol and recolored or made transparent.

another method is to make a new layer for your shadows. copy paste in place areas that need the shadow, and modify the shape into the shadow shape. fill with the transparent color, and you will see through the shadow to the lines below.

Add color and gradients ... keep the shadows on one separate layer and control their transparency together.