multiple product types – woocommerce

I’m looking a way to add multiple product types to a woocommerce product.

In fact, i use an extra plugin from codecanyon to create mix match custom boxes, and i wish to add size variation of this product.

Perhaps, when i switch product type to “custom box” i loose the variation settings.

I already try different things, like setting both, but it never display on front end.

thanks in advance for your help