$order_details array inside delivery-slip.tpl has wrong location for combination products

[prstshp_joe]

I'm struggling to figure out how to fix this. 

 

I'm trying to show the product location for the warehouse to do the picking, so I modified the "delivery-slip.tpl" and changed to show the location instead of the reference.

 

{$product.location} shows always the correct information stored inside the "products" table, but for combination products it will show the main product location instead.

 

I believe that somewhere there's a wrong JOIN statement with "product_id" instead "product_attribute_id" but I can not find it.

 

Anyone knows where I can fix this? Thx!