Custom Invoice Numbers

I have trialled Reckon One, and the BIG thing holding us back migrating across is the inability to create our own custom invoice numbers. We have our own numbering protocol, and Reckon One doesn't let us enter our numbering system for invoicing. We don't want to be limited to a basic sequential numbering system that Reckon One thinks is suitable for all customers. We want to have the ability to create our own invoicing numbering system, be able to reset and change invoice numbers, and add prefixes and suffixes as required. We want total flexibility. Why is this so restricted? It should be up to the end user, not hard locked down by the software. There is no legal requirement for our invoice numbers to be locked down in your ordering restrictions. We can choose our own numbering methodology. Please allow your customers to create their own invoice numbering protocol however they see fit. This should be an easy fix, yet it is stopping us from migrating across to your software.