Adding a column to Unposted Mass Additions Report from FA_Mass_Additions table

Hello,

 I'm trying to determine in R12 if there is a way to add a column to a selection of attributes so that I could take that column and add it into the report. 

  There is mention of using the Report eXchange Designer responsibilty but I don't see the Unposted Mass Additions Report as an RX choice. 

   HOw is the RX only Mass Additions Report different from Unposted Mass Additions Report.   In our test region I've run both on the same Books/Ledger and in the RX I get no results but find results in Unposted..report.

  In the RX-- one that column is not selectable from the attributes.