Today, we use another system for writting checks and we need to add the check information to Xero.

The API allows us to create an invoice for the check and then upload the invoice. However, the API does not allow us to associate a bank account and then check number with the payment of the invoice.

I know that there is some reason that this the case. There could be an instance where a user tries to associate a previously used check number to the invoice payment. If Xero were to throw a blanket error (eg, "Some of the transactions in this API call use a check number that has already been used and so none of the transactions have been imported.")

Exposing the check number and then handling errors would be of great benefit for us.