Combine general shipping with product specific shipping for order with only specific shipping

[Chamaf]

Hello!

I have a quick request!

I have a general shipping profile with flat rates based on total order value for all my products, lets call these product x, except two special products that we can call y that i need to charge extra shipping for. 
I want both of these rates to add up when a customer places an order that includes a product y. 

Currently this works great when an order contains product x and product y. However if an order only contain product y, only the special shipping is charged, which is too low. Is there anyway to solve this?

In essence i want shipping from the general profile and the product shipping profile to add up even when the order only contains product from product shipping profile.

Regards