How to encode a payment schedule

[David Goodenough <david.goodenough@broadwellmanor.co.uk>]

There are occasions where an invoice should be paid in installments.  A few examples:-

1) Upfront payment for parts, post completion payment for labour.  This is quite common for invoices from small/sole traders at least in the UK

2) Finance payments over several years.

In a PaymentMeans the second of these can be indicated as TradeFinancing which effectively redirects the payment to the finance party, but there seems to be a missing object, a PaymentSchedule, which one would assume would contain a list of scheduled payments each of which would contain either a date or a condition (e.g. completion) and an amount where the amounts add up to the invoice total.  The RemittanceAdvice would then have to have a reference to a PaymentSchedule line.

Have I missed something, or is this a candidate for addition to UBL 2.{x>3}?

David