Need a Discount Column in Refund Returns page

Hey all,

I'm looking to add a column on the Refund Returns page to list the discount applied to the Return Authorization. 

I know that the field for the discount on sale is {discount item}, but I can't figure out how to get it to populate on the page.  I created a custom transaction column with {discountitem} as default and selected it from the sublist to customize my view, but nothing appears on the page.

I'm stumped....any ideas?

Thanks,
Thomas