If you have products in your order both from AliExpress and Sellvia the system will ignore the Sellvia products if you process an order with AliExpress and the system will ignore AliExpress products if you process your order with Sellvia (even if AliExpress products are displayed as not found on Sellvia order processing screen).
Good to know this thanks. I think I'am all done with integrating both. Not a pretty solution but will work in the end. I'll keep testing and will let know.