How do I search for an order by it's internalId or externalTransactionId?

My payment system gives me internalId of the order and not the id. So it's impossible to match payment transaction and an order in ecwid panel. API also does not allow searching either by internalId or externalTransactionId fields so I can't write a custom matcher app.

It would be very convenient to make those fields searchable to allow matching such payment transactions to to actual orders.