Creating a Custom Date Field for Sales Orders and Invoices

How can I create a Custom Field column on a Sales Order that is formatted as a date?

I am trying to run an Open Sales Orders by Item Ship Date report or an Open Sales Orders by Item (and then be able to sort by Item Ship Date. We need to be able to put an Item Ship Date for each Line Item on a Sales Order.

So far, I was able to create a Custom Field column and name it "Item Ship Date" by following this:

QuickBooks Desktop for Windows

1. Go to the Lists menu and select Item List.
2. Double-click any item on the list to open and edit it.
3. Select Custom Fields. Then select Define Fields. 
   Name your custom field in the Label column. Names aren't case-sensitive.
4. In the Use column, select the checkbox to turn on the custom field.
5. Select OK to save the custom field.

However, under "Set Up Custom Fields for Items", I do not have any options except Label and Use. None of the other options are available. Even if they were, I'm not sure that the "What Kind of Data" option offers "Date".