Qty on Backorder

G’day,
I notice no backorder quantity is currently possible.
For instance;

  1. I raise a Sales Order for 2x FG - S/O 1234
  2. I raise a Delivery Note for 1x of the FG from S/O 1234.

To show that their is still 1 more to be shipped, I have to say so on the Notes on the Delivery Note.
I’m used to using software which asks me how many will be shipped for a particular Delivery Docket/Note, from which it returns a backorder quantity - Eg. it knows that 2 are to be shipped for the order, and I tell it that 1 are being shipped for this particular Delivery, and it shows that 1 will be still be on backorder.

Cheers