Manually Add Back Dated Order via Admin

Has anyone had any success / found a way to manually add a 'back dated' order?

We manually process some orders where customers enquire via the site but for one reason or another much of the donkey work is completed offline, including payment. We then need to ensure that the order is added to CS-Cart to keep the data complete and ensure that the sales are being recorded to the right revenue stream! This can overlap month end / start and would like to keep the order in the actual month of the order rather than when it is processed!

I can of course 'bend' the data via the back-door but would prefer to do this via Admin so that office users can perform the function rather than it falling to me each time!!!