XL Report Requirement - AP Docs incl. Pay. Terms

Hi all,

i'm about to create a user specific report, using XL reporter. Setting up the report to come up with all open AP Invoices has not been a big deal. Now i want to also show the payment discount, to calculate in the XL report. e.g. AP Doc total is 100u20AC, payment term is 14days 2%, 30days net. couldn't find a solution calculating the 100u20AC minus 2%. Anyone an idea how to handle that..?

BR - Dominic