Why is Due Date not an option in Sales Register?

I want to create a Sales Register report, but by default the "date" displayed is the creation date.  So I want to therefore customise the report, by adding Due Date.  

For some reason, EVERY OTHER field is available in the Customise list to add EXCEPT Due Date!  Why is that?  Due Date would be the most obvious other field to add, and I can't add it!

Conversely, if I try the same thing withe customising the Purchases Register report, I have the ability to add the Due Date?

I tried Promised Date, and it just shows nothing. Interestingly, there is no where on any invoice form the place to enter Promised date. How do I even use Promised Date?

I tried Days til paid - blank.

I read elsewhere to try Receiveables report reconciliation, but MYOB says "Failed to load report"

I am using MYOB Business Pro.

Can we update this report so that Due date is included in the customisation list, given every other field is there?

Thanks!