Have you tried looking at the Sale Rep reports instead?
sp_report SalesByRepDetail show SalesRep, Text, Blank, TxnType, Date, RefNumber, Memo, Name, Item, Quantity, UnitPrice, Amount, RunningBalance parameters DateMacro = 'ThisMonthToDate'
or:
sp_report SalesByItemDetail show SalesRep, Text, Blank, TxnType, Date, RefNumber, Memo, Name, Quantity, UnitPrice, Amount, RunningBalance parameters DateMacro = 'ThisMonthToDate' where SalesRep='YourRepsName' |