Like other four letter words, UDFs flow downhill. AR Customer Master, SO Ship to => SO => Invoice (this one is tricky, makes me pause every time) => AR transactionposting => AR open invoice and/or AR Invoice History and then don't forget to loop back to SO and/or invoice in case you want to create a SO or invoice from invoice history. And for good measure, don't forget the SO, Picking sheet, Packing list WRK files and then the related Crystal forms in case you want the UDF to appear on the forms.... Whew!!