We need to send through a custom id when creating an invoice and to be able to retrieve that id from the returned invoice object. i.e. before adding invoice items from our internal billing system.
I have been trying to use the comments field as the api docs state that you can pass in and it will be included in the invoice object when it is returned by FA.
I have tried this but unfortunately never appear in my returned invoice.
We have been using FA and this api for years so we know that our process is fundamentally sound but this is the first time that we have needed to pass through and retrieve a custom value.
Can anyone shed any light/offer ideas ?