Paulo,
I do understand the CO-FI integration is a separate topic 
, but we do have a use here. It will not substitute the billing process but should act as source to billing.
I was just trying to use cross company cost allocation to serve as basis for RRB. In DIP profile we have an option of source as " Actual line items" and " Intercompany line items".
I was trying to trigger RRB on " Intercompany line items". What you are suggesting above will be triggered on "Actual line items". We don't have any trigger point for Intercompany line items. It's regular SO-PO scenario.
Also, in your scenario, you will have to bill the customer for Colombian employee at costs +% basis, as you have no collection of Colombian employee activity in US WBS. My requirement is to bill end customer on basis of Hours booked.