How we can associate Invoice lines in the existing Purchase Order Trade Operations.

We've created trade operations for Purchase Order to do Estimated landed cost calculation. Now we need to associate invoice on PO in Trade Operation for Actual Landed Cost Calculation. From front end, we're able to do this. But we want to automate this process via OIC Integration. Are there some Rest API's available to do so. We tried from Oracle docs, but not much useful.

Thank you.