importing into unity unsing fbx - not all meshes are shown/imported

Hi together,
I have built a character connected to an armature and using shape keys.
The character has eyes as separate objects, which are controlled by some bones of the armature.
I created some animations and in blender everything is fine.
if I just drop the .blend file into the assets of a unity project, everything seems to work as it should - apart from the shape keys not being imported.
If I use the FBX exporter and drop the fbx file into assets, the animations are shown beautifully (including the shape key animations) in the preview of the takes BUT when I drop the model into the scene the eyes are missing. I played around with the settings of the FBX exporter (explicitly selecting all meshes etc) but still - the eyes are missing.
please help - slowly but surely becoming insaneā€¦!!!
best, ina