I have a multi-company setup, some companies with multiple bank accounts (each in a different currnecy).

I have a portal that accepts payments and that portal needs to put those payments against invoices that the user has open. I have a library for calling up methods on models over the API to do this.

To make these payments, we create vouchers and voucher lines, then push them through workflow. Technically this is working, but some of the data in those vouchers needs to be derived.

One example is the journal_id - where would I get that from? I want to make the payment against a bank account for the invoice issuer (a company) that handles the same currency as the invoice. Which models do I need to look at and which relationships do I need to follow to get to the appropriate journal_id?

Thanks.