Forecast Demand Reference

We have always used DMT to enter our forecast and have utilised the DemandRefernce field to note the Branch/SalesRep responsible for the forecast. In Classic this was visible in timephase however in Kinetic it is not and I cannot see it in application studio to add.

Investigation indicates this is an EDI field which we do not have. Is my only option to add a UD field is that possible? would it go on the PartDtl table as I’m not seeing anything for timephase