Inventory Committment - Sales Order Entry

We are entering sales orders as follows:

1) order is entered for item 01A for quantity of 1 unit.

2) Item 01A has zero available and zero on hand.

3) Item does not go on backorder nor does it WARN me there is no availability to meet order.

I have checked processing options for commitment (Tab 5, Option 1 is set to 1), and it is set to WARN us, but it also should also backorder the line.

However, if we enter a different sales order as such:

1) Order is entered for item 02A for a quantity of 6 units.

2) Item 02A has 5 on hand and 5 available

3) System WARNS us of that we cannot fill the order and order entry splits the line to ship 5 and backorder 1.